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Sample records for leurs spectres uv

  1. Sympathy for the Spectres

    DEFF Research Database (Denmark)

    Graham, Brian Russell

    2012-01-01

    Med Brian Grahams artikel “Sympathy for the Spectres: The Double Nature of Blake’s Spectral Figures in Jerusalem” forbliver vi inden for den litterære tradition, men bevæger os en smule længere frem i tiden. Graham retter blikket mod William Blakes forfatterskab og påpeger, at Blakes univers er...... feministisk synsvinkel – er spøgelserne dobbelte: de spiller en rolle i kristendommens historie, samtidig med at de spiller en kontrasterende sympatisk rolle i den universelle strid mellem Blakes ”male and female powers”, denne evige strid mellem disse to poler ses af Blake som grundlaget for al skabelse og...

  2. SUR UNE CERTAINE CLASSE D’OPERATEURS A SPECTRE CONCENTRE EN UN POINT DANS UN ESPACE DE HILBERT

    Directory of Open Access Journals (Sweden)

    B BENDOUKHA

    2000-12-01

    Full Text Available Le présent travail est consacré à l'étude de certaines classes d’opérateurs qui sont parfaitement définis par leur spectre. Pour ces opérateurs (définis dans des espaces de Hilbert abstraits, on donnera une représentation explicite et uniquement à l’aide du spectre dans l’espace des fonctions à carrés intégrables.

  3. Synthesis and purification of some alkyl phenanthrenes and presentation of their infrared, ultraviolet, nuclear magnetic resonance and mass spectra; Synthese et purification de quelques alcoylphenanthrenes et presentation ds leurs spectres d'absorption infrarouge, ultraviolette, de resonance magnetique nucleaire et de masse

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-01-01

    We have carried out the synthesis of: - phenanthrene - its five monomethyl derivatives - three dimethyl derivatives - two trimethyl derivatives. We have then purified these products as well as a certain number of others obtained from various sources. We have been able to obtain in the majority of cases, a purity of 99.5 per cent or over, these figures being obtained by low voltage mass spectrometry. Finally we have recorded the infrared, ultraviolet, nuclear magnetic resonance and mass spectra of these products for which an atlas has been drawn up. (author) [French] Nous avons realise la synthese: - du phenanthrene - de ses cinq derives monomethyles - de trois de ses derives dimethyles - de deux de ses derives trimethyles. Nous avons ensuite purifie ces produits ainsi qu'un certain nombre d'autres que nous avons obtenus de sources differentes. Nous avons pu atteindre, dans la plupart des cas, une purete egale ou superieure a 99,5 pour cent, chiffres determines par la spectrometrie de masse a basse tension. Enfin, nous avons enregistre les spectres infrarouges, ultraviolets, de resonance magnetique nucleaire et de masse de ces produits dont nous avons fait un atlas. (auteur)

  4. SPECTR System Operational Test Report

    International Nuclear Information System (INIS)

    Landman, W.H. Jr.

    2011-01-01

    This report overviews installation of the Small Pressure Cycling Test Rig (SPECTR) and documents the system operational testing performed to demonstrate that it meets the requirements for operations. The system operational testing involved operation of the furnace system to the design conditions and demonstration of the test article gas supply system using a simulated test article. The furnace and test article systems were demonstrated to meet the design requirements for the Next Generation Nuclear Plant. Therefore, the system is deemed acceptable and is ready for actual test article testing.

  5. Spectrum stabilizer; Stabilisateur de spectres

    Energy Technology Data Exchange (ETDEWEB)

    Detourne, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires, Departement d' electronique generale, Service d' instrumentation nucleaire

    1967-05-01

    A spectrum stabilizer is a control mechanism which renders an analytical chain reliable. It can detect a drift in the amplification and in the base of the energy scale, and can modify the characteristics of this chain. The results of a theoretical study make it possible to calculate the width and the abscissae of the peaks of a stabilized spectrum as a function of the drifts. The SPECTROSTAB is a numerical stabilizer of a continuous type; it provides the artificial reference peak at low energies. Experimental results give the performances obtained on a reference peak provided by a semi-conductor detector, in the field of gamma spectroscopy. (author) [French] Un stabilisateur de spectres est un asservissement qui permet de rendre fidele une cha e d'analyse. Il detecte les derives du gain et de l'origine de l'echelle des energies et reagit sur les caracteristiques de cette cha e. Les resultats d'une etude theorique permettent le calcul des elargissements et des abscisses des pics d'un spectre stabilise, en fonction des derives. Le SPECTROSTAB est un stabilisateur numerique du genre continu; il fournit le pic de reference artificiel aux basses energies. Des resultats experimentaux donnent les performances obtenues sur un pic de reference fourni par un detecteur a semi-conducteur, dans le domaine de la spectrometrie gamma. (auteur)

  6. Measurements of spectral indices in homogeneous multiplying media; Mesures d'indices de spectre dans les milieux multiplicateurs homogenes

    Energy Technology Data Exchange (ETDEWEB)

    Bruna, J G; Brunet, J P; Clouet D' Orval, Ch; Verriere, Ph; Kremser, J; Moret-Bailly, J; Tellier, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Methods for computation of spectra in light water are developed at Saclay and it is interesting to carry out at the same time experimental studies of simple media such as solutions of fissionable salts which allow quite direct comparisons with computed values. The spectral indices measurements were made with two small fission chambers, one containing deposited plutonium, the other deposited uranium 235. Their response, when neutron spectrum is modified, allows to study the epithermal part of the flux. The media studied with these chambers are fissionable solutions (of plutonium or 90 per cent enriched uranium) which were made critical in bare cylindrical geometry in the Alecto reactor. If the ratio of the chambers is normalized to unity in a Maxwell spectrum, then the noted variation of the ratio of the counts Pu chamber/ U{sup 235} chamber reaches 1,4 in the range of the studied concentrations. (authors) [French] Des calculs de spectres dans l'eau legere sont mis au point a Saclay et il est interessant de mener parallelement des etudes experimentale sur des milieux simples tels que des solutions de sels fissiles, qui permettent des comparaisons tres directes avec les valeurs calculees. On a choisi d'effectuer des mesures d' 'indices de spectres' a l'aide de de deux petites chambres a fission contenant des depots, l'une de plutonium, l'autre d'uranium 235. Leur reponse lorsque le spectre des neutrons est modifie permet d'etudier la partie epithermique du flux. Les milieux etudies a l'aide de ces chambres sont des solutions fissiles (plutonium ou uranium enrichi a 90 pour cent) rendus critiques, en geometrie cylindrique nue, dans le reacteur Alecto. Si le rapport des chambres est normalise a un dans un spectre de Maxwell, la variation constatee du rapport des comptages chambre Pu/ chambre U{sup 235} atteint, dans les gammes de concentrations etudiees, 1,4. (auteurs)

  7. Infra-red spectra of systems containing hydrogen-bonds; Spectres dans l'infrarouge de corps a liaison hydrogene

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    du type X-H...Y et X-H...Y. En supposant que le mouvement X-H...Y est harmonique, mais depend parametriquement de la distance X...Y, et en tenant compte de l'interaction entre differentes liaisons hydrogene, nous pouvons reconstituer quantitativement les spectres des corps tels que l'imidazole et les dimeres d'acide acetique, qui forment les spectres les mieux resolus experimentalement. L'effet isotopique (remplacement de H par D) decoule tout naturellement de cette supposition, et le spectre experimental des corps deuteres est reconstitue quantitativement, sans aucune hypothese supplementaire, ce qui nous donne une confirmation independante de la validite de notre theorie. Nous etendons ces considerations au cas de cristaux a liaison hydrogene en vue d'une reconstitution future de leurs spectres infrarouge. Par sa signification physique, notre theorie s'oppose aux theories proposees anterieurement, qui ne tenaient pas compte de ce mecanisme de couplage ni de l'interaction entre liaisons hydrogene. Ces theories anterieures n'ont pas recu, a notre connaissance, de verification quantitative. Aussi notre reconstitution quantitative des spectres a structure complexe de l'imidazole et de l'acide acetique, ainsi que notre prevision correcte de l'effet isotopique, semblent indiquer que le mecanisme propose est le facteur principal qui intervient dans les differents mouvements d'elongation de la liaison hydrogene. (auteur)

  8. Infrared Fourier spectres of pectin obtained from pumpkin

    International Nuclear Information System (INIS)

    Usmanova, S.R.; Dzhonmurodov, A.S.; Nazirova, Kh.I.; Mukhidinov, Z.K.

    2015-01-01

    Present article is devoted to infrared Fourier spectres of pectin obtained from pumpkin. The analysis of pectin obtained from pumpkin was conducted by means of infrared spectrophotometer with Fourier transformation. The infrared spectroscopic study of pectin polysaccharide fraction of pectin matter, as well as pectin helium and micro helium obtained by means of fast extraction was conducted.

  9. Shades of Freire: Exorcising the Spectre Haunting Pedagogy

    Science.gov (United States)

    Wilkins, Andrew

    2013-01-01

    In the second part of this special issue on neoliberalism, pedagogy and curriculum, I explore the contributions of each author to confronting neo-liberal reforms of education, notably the spectre of neo-liberalism haunting aspects of pedagogy, teaching and curriculum. Exemplary of the scholarly work produced by many critical educators, the…

  10. On the behaviour of the spectre of surface waves in a uniform rotating fluid

    International Nuclear Information System (INIS)

    Fraguela Collar, A.

    1990-10-01

    This work is devoted to the study of the spectre of surface waves arising in the linear oscillations problem of a portion of an ideal heavy non capillary liquid constrained into a vessel with interior spatial domain U. In the present work we will be concerned with the following two equations: Under which conditions on U and V (volume of liquid enclosed into U) is it possible to assure non existence of discrete spectre of superficial waves in the threshold of the inner wave spectre? How do spectre of superficial waves depend on local variations of angular speed? (author). 5 refs

  11. CALCUL DU SPECTRE DE REFLEXION DU MULTICOUCHE Ni/C DANS LE DOMAINE DES RAYONS X

    Directory of Open Access Journals (Sweden)

    A MEDDOUR

    2000-12-01

    Full Text Available Le pouvoir réflecteur d’un dioptre quelconque dans le domaine des rayons X est trop faible, mais il est toujours possible de choisir des systèmes pouvant présenter un pic de réflexion d’intensité importante autour d’une incidence caractéristique du matériau. Ce dernier est un multicouche, composé de deux couches déposées en sandwich.                 Nous avons élaboré un programme qui permet de calculer la réflexion d’un tel matériau en suivant la méthode d’Abelès dans laquelle une couche mince est représentée par une matrice carrée contenant toutes les informations nécessaires pour le calcul de la réflexion. Ce programme tient compte aussi des rugosités aux interfaces du multicouche, vue leur importante influence sur l’intensité du pic apparaissant sur le spectre de réflexion.                 L’application du programme au multicouche Ni/C a montré  l’existence d’un pic centré autour de 31.32°. Son intensité est sensible au nombre de périodes dans le multicouche, aux épaisseurs des couches minces de Ni et de C et à la taille des rugosités des interfaces Ni/C et C/Ni.

  12. Self-association and infrared spectres of some heterocyclic compounds based on pyrrol in solid state

    International Nuclear Information System (INIS)

    Mulloev, N.; Nurulloev, M.; Narziev, B.N.

    1993-01-01

    Present article is devoted to self-association and infrared spectres of some heterocyclic compounds based on pyrrol in solid state. The study results of self-association specified by molecular hydrogen bonds of some heterocyclic compounds based on pyrrol on spectres of infrared absorption of stretching vibrations of N-H group were considered.

  13. Neutron thermalization and spectra; Thermalisation et spectres de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cadilhac, M; Soule, J L; Tretiakoff, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    interpretation of experiments (spectral indices critical experiments on plutonium, diffusion parameters). (authors) [French] L'etude des spectres de neutrons regnant dans les reacteurs thermiques a pris une importance croissante en raison du role qu'y joue le plutonium. Quelle que soit par ailleurs la loi d'absorption, on constate que la loi de diffusion du moderateur n'agit sur le spectre que par certaines proprietes globales. Il est donc a priori possible de mettre au point une representation simplifiee de cette action, qui conduise a une comprehension claire des phenomenes tout en reduisant le volume des calculs numeriques necessaires. Le modele synthetique adopte par les auteurs presente l'avantage de ramener la determination des-spectres en milieu homogene a la resolution d'une equation differentielle du second ordre, comme le modele de Wigner-Wilkins (hydrogene gazeux monoatomique) et le modele gaz lourd generalise de J. Horowitz, qui en sont d'ailleurs l'un et l'autre des cas particuliers. Mais il est d'autre part assez general pour permettre de traiter correctement les situations rencontrees en pratique et en particulier le cas important ou la presence de plutonium fait apparaitre des resonances d'absorption a basse energie. Les liaisons chimiques ou cristallines du moderateur interviennent en effet, dans le modele propose, par l'intermediaire de deux fonctions de l'energie. Ces fonctions ont ete ajustees, pour les moderateurs usuels (Graphite. Eau lourde. Eau legere), a partir de lois de diffusion theoriques connues. En milieu heterogene, il importe avant tout de bien connaitre le spectre moyen dans le combustible d'une cellule ce que permet une generalisation de la methode d'Amouyal-Benoist-Horowitz. Le modele presente se prete particulierement bien a ces calculs et permet de traiter egalement les effets de rethermalisation (lorsque par exemple le refroidisseur est a une temperature differente de celle du moderateur). On donne enfin des exemples d'utilisation pratique

  14. Konstruksi Realitas Pengguna Ponsel Cerdas Berdasarkan Pesan Penempatan Merek dalam Film James Bond: Spectre

    OpenAIRE

    Hafiz, M. Faisal

    2016-01-01

    This study entitled "Construction of Reality of Smartphone User Based on Branding Placement Message in James Bond: Spectre Film". The research is going to examine the relations between the process of branding placement of Sony Xperia Z5 to the movie-viewer who use smartphone from a variety of backgrounds. Researcher focus on how smartphone users adapt to their social needs, how subjective meaning of Sony Xperia Z5 upon the branding placement message in James Bond: Spectre, a...

  15. ETUDE STRUCTURELLE ET SPECTRES D’ABSORPTION DE Kr3+

    Directory of Open Access Journals (Sweden)

    A CHIKHAOUI

    2001-12-01

    Full Text Available Le présent travail, qui comporte deux étapes, est une étude théorique de l'agrégat de Krypton chargé une fois (Kr3+. La première étape est l'étude structurelle de Kr3+. L'hamiltonien modèle est développé dans le cadre de la méthode D.I.M (Diatomics In Molecules. Les résultats obtenus montrent que Kr3+ est linéaire. La profondeur du puits attractif De est égale  à 0.29 eV par rapport à la dissociation en Kr2+ + Kr pour une distance d'équilibre Re = 5.496 u.a. Ce résultat est en bon accord avec la valeur expérimentale qui vaut 0.27 eV. La deuxième étape est l'étude thermodynamique et spectroscopique de Kr3+. Les résultats obtenus montrent que le spectre vertical de Kr3+ linéaire comporte trois pics situés dans le domaine du visible à 625nm, 551nm et 466nm. L'analyse statistique des populations de charges atomiques montre que Kr3+ subit une isomérisation qui le ramène à une configuration de type ( Kr2+ ...Kr ou à une configuration plus probable de type  (Kr+...Kr2 .

  16. Gamma spectrum measurement in a swimming-pool-type reactor; Mesure du spectre {gamma} d'une pile piscine

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    After recalling the various modes of interaction of gamma rays with matter, the authors describe the design of a spectrometer for gamma energies of between 0.3 and 10 MeV. This spectrometer makes use of the Compton and pair-production effects without eliminating them. The collimator, the crystals and the electronics have been studied in detail and are described in their final form. The problem of calibrating the apparatus is then considered ; numerous graphs are given. The sensitivity of the spectrometer for different energies is determined mainly for the 'Compton effect' group. Finally, in the last part of the report, are given results of an experimental measurement of the gamma spectrum of a swimming-pool type reactor with new elements. (author) [French] Apres un rappel des differents modes d'interaction des rayons gamma avec la matiere, nous decrivons la conception d'un spectrometre pour les energies gamma s'etendant de 0,3 a 10 MeV. Ce spectrometre utilise les effets Compton et creation de paires sans les eliminer. Le collimateur, les cristaux et l'electronique sont entierement etudies et decrits dans leur realisation definitive. Ensuite, le probleme de l'etalonnage de l'appareil est envisage; de nombreuses courbes sont donnees. La sensibilite du spectrometre pour les differentes energies est determinee principalement pour le groupe ''effet Compton''. Enfin, les resultats d'une experience de mesure du spectre gamma d'une pile piscine avec elements neufs sont donnes dans la derniere partie. (auteur)

  17. The factographic database on atomic spectroscopy ''spectr-2'' for information service in the field of thermonuclear and quantum electronic investigations

    International Nuclear Information System (INIS)

    Bugaev, V.Yu.; Pal'chikov, V.G.; Skobelev, I.Yu.; Faenov, A.Ya.

    1990-01-01

    ''Spectr-2'' automated database in an extension of ''Spectr-1'' database developed in VNIIFTRI (USSR) for storage and rapid search of multicharged ions atomic characteristics. The information structure, the interaction of the terminal user and the information accumulation in this database are described. 4 figs

  18. CytoSpectre: a tool for spectral analysis of oriented structures on cellular and subcellular levels.

    Science.gov (United States)

    Kartasalo, Kimmo; Pölönen, Risto-Pekka; Ojala, Marisa; Rasku, Jyrki; Lekkala, Jukka; Aalto-Setälä, Katriina; Kallio, Pasi

    2015-10-26

    Orientation and the degree of isotropy are important in many biological systems such as the sarcomeres of cardiomyocytes and other fibrillar structures of the cytoskeleton. Image based analysis of such structures is often limited to qualitative evaluation by human experts, hampering the throughput, repeatability and reliability of the analyses. Software tools are not readily available for this purpose and the existing methods typically rely at least partly on manual operation. We developed CytoSpectre, an automated tool based on spectral analysis, allowing the quantification of orientation and also size distributions of structures in microscopy images. CytoSpectre utilizes the Fourier transform to estimate the power spectrum of an image and based on the spectrum, computes parameter values describing, among others, the mean orientation, isotropy and size of target structures. The analysis can be further tuned to focus on targets of particular size at cellular or subcellular scales. The software can be operated via a graphical user interface without any programming expertise. We analyzed the performance of CytoSpectre by extensive simulations using artificial images, by benchmarking against FibrilTool and by comparisons with manual measurements performed for real images by a panel of human experts. The software was found to be tolerant against noise and blurring and superior to FibrilTool when analyzing realistic targets with degraded image quality. The analysis of real images indicated general good agreement between computational and manual results while also revealing notable expert-to-expert variation. Moreover, the experiment showed that CytoSpectre can handle images obtained of different cell types using different microscopy techniques. Finally, we studied the effect of mechanical stretching on cardiomyocytes to demonstrate the software in an actual experiment and observed changes in cellular orientation in response to stretching. CytoSpectre, a versatile, easy

  19. Shelley Jones — Aider les jeunes Ougandaises à poursuivre leurs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    18 nov. 2014 ... ... d'entre elles abandonnent l'école à cause de leur cycle menstruel. ... Shelley Jones with her Masters of Education students debating gender issues ... limité ou à la discrimination sexospécifique en matière d'éducation.

  20. SPECTR-W3 online database on atomic properties of atoms and ions

    International Nuclear Information System (INIS)

    Faenov, A.Ya.; Magunov, A.I.; Pikuz, T.A.; Skobelev, I.Yu.; Loboda, P.A.; Bakshayev, N.N.; Gagarin, S.V.; Komosko, V.V.; Kuznetsov, K.S.; Markelenkov, S.A.; Petunin, S.A.; Popova, V.V.

    2002-01-01

    Recent progress in the novel information technologies based on the World-Wide Web (WWW) gives a new possibility for a worldwide exchange of atomic spectral and collisional data. This facilitates joint efforts of the international scientific community in basic and applied research, promising technological developments, and university education programs. Special-purpose atomic databases (ADBs) are needed for an effective employment of large-scale datasets. The ADB SPECTR developed at MISDC of VNIIFTRI has been used during the last decade in several laboratories in the world, including RFNC-VNIITF. The DB SPECTR accumulates a considerable amount of atomic data (about 500,000 records). These data were extracted from publications on experimental and theoretical studies in atomic physics, astrophysics, and plasma spectroscopy during the last few decades. The information for atoms and ions comprises the ionization potentials, the energy levels, the wavelengths and transition probabilities, and, to a lesser extent, - also the autoionization rates, and the electron-ion collision cross-sections and rates. The data are supplied with source references and comments elucidating the details of computations or measurements. Our goal is to create an interactive WWW information resource based on the extended and updated Web-oriented database version SPECTR-W3 and its further integration into the family of specialized atomic databases on the Internet. The version will incorporate novel experimental and theoretical data. An appropriate revision of the previously accumulated data will be performed from the viewpoint of their consistency to the current state-of-the-art. We are particularly interested in cooperation for storing the atomic collision data. Presently, a software shell with the up-to-date Web-interface is being developed to work with the SPECTR-W3 database. The shell would include the subsystems of information retrieval, input, update, and output in/from the database and

  1. Spectr-W3 Online Database On Atomic Properties Of Atoms And Ions

    Science.gov (United States)

    Faenov, A. Ya.; Magunov, A. I.; Pikuz, T. A.; Skobelev, I. Yu.; Loboda, P. A.; Bakshayev, N. N.; Gagarin, S. V.; Komosko, V. V.; Kuznetsov, K. S.; Markelenkov, S. A.

    2002-10-01

    Recent progress in the novel information technologies based on the World-Wide Web (WWW) gives a new possibility for a worldwide exchange of atomic spectral and collisional data. This facilitates joint efforts of the international scientific community in basic and applied research, promising technological developments, and university education programs. Special-purpose atomic databases (ADBs) are needed for an effective employment of large-scale datasets. The ADB SPECTR developed at MISDC of VNIIFTRI has been used during the last decade in several laboratories in the world, including RFNC-VNIITF. The DB SPECTR accumulates a considerable amount of atomic data (about 500,000 records). These data were extracted from publications on experimental and theoretical studies in atomic physics, astrophysics, and plasma spectroscopy during the last few decades. The information for atoms and ions comprises the ionization potentials, the energy levels, the wavelengths and transition probabilities, and, to a lesser extent, -- also the autoionization rates, and the electron-ion collision cross-sections and rates. The data are supplied with source references and comments elucidating the details of computations or measurements. Our goal is to create an interactive WWW information resource based on the extended and updated Web-oriented database version SPECTR-W3 and its further integration into the family of specialized atomic databases on the Internet. The version will incorporate novel experimental and theoretical data. An appropriate revision of the previously accumulated data will be performed from the viewpoint of their consistency to the current state-of-the-art. We are particularly interested in cooperation for storing the atomic collision data. Presently, a software shell with the up-to-date Web-interface is being developed to work with the SPECTR-W3 database. The shell would include the subsystems of information retrieval, input, update, and output in/from the database and

  2. Raman spectra of ordinary and deuterated liquid ammonias; Spectres Raman des ammoniacs ordinaire et deuteries liquides

    Energy Technology Data Exchange (ETDEWEB)

    Ceccaldi, M; Leicknam, J P [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, direction des materiaux et des combustibles nucleaires, departement de physico-chimie, service des isotopes stables, service de spectrometrie de masse

    1968-12-01

    The three deuterated ammonia molecules, as well as ordinary ammonia, have been examined in the liquid state by Raman spectroscopy using a high-pressure cell described elsewhere. This work thus completes the infrared spectrometry studies. We have examined the NH and ND valency absorption regions. The polarization measurements and isotope effect considerations make it possible to confirm most of the attributions recently proposed for interpreting the infrared spectra of the four isotopic molecules: the apparent disagreement between the NH{sub 3} and ND{sub 3} spectra obtained in this region by infrared and Raman spectroscopy is discussed: by the first technique the number of bands in the spectra corresponds well to the theoretically expected number, and the relative intensities conform more or less to expectations; the Raman spectra however have a strong supplementary band in the same region, produced by a Fermi resonance; it is possible to explain, from theoretical considerations, why this resonance appears so easily in the Raman spectrum, whereas it is detected in the infrared only by a very detailed analysis of the effects of solvents on the ammonia. (authors) [French] Les trois ammoniacs deuteries, ainsi que l'ammoniac ordinaire, sont examines a l'etat liquide par spectrometrie Raman, a l'aide d'une cuve haute pression decrite par ailleurs. Ce travail complete donc les etudes effectuees par spectrometrie infra-rouge. Nous avons examine les regions d'absorption de valence NH et ND. Les mesures de polarisation et des considerations sur les effets isotopiques permettent de confirmer la plupart des attributions proposees recemment pour interpreter les spectres infra-rouges des quatre molecules isotopiques: on discute egalement l'apparent desaccord entre les spectres de NH{sub 3} et de ND{sub 3} obtenus dans cette region par infra-rouge et Raman: par la premiere technique le nombre de bandes relevees sur les spectres correspond bien au nombre theoriquement attendu et

  3. Les enseignants: à la recherche de leur profession

    OpenAIRE

    Nóvoa, António, 1954-

    1994-01-01

    Les Enseignants: à la recherche de leur profession reprend les idées centrales présentées à la Conférence donnée, sur l'invitation de l'ATEE, au Séminaire de Barcelone, en 1993. Cet article est la reproduction du texte de support à la Conférence. Étant donné l'espace disponible, il n'a pas été possible de le travailler dans le sens d'une plus grande problématisation et élaboration théorique.

  4. Study of some continuous spectra produced by nuclear reactions with light nuclei; Etude de quelques spectres continus produits par reactions nucleaires avec des noyaux legers

    Energy Technology Data Exchange (ETDEWEB)

    Marquez, L

    1966-07-01

    The continuous spectra coming from several nuclear reactions with light nuclei were measured. The spectra can be explained by a two-step reaction mechanism; however, the reactions produced by {sup 6}Li are different. A mechanism was proposed to explain their spectra based on the following assumptions: {sup 6}Li makes a nuclear molecule with the target which subsequently breaks up in such a way that an {alpha} particle comes out with the kinetic energy that it has in the molecule. The calculated spectra and those measured are in good agreement. (author) [French] Nous avons mesure les spectres continus produits dans plusieurs reactions nucleaires avec des noyaux legers. A l'exception des spectres produits par {sup 6}Li, on a trouve qu'on pouvait expliquer ces spectres par le mecanisme des reactions en deux etapes. Nous avons propose un mecanisme pour expliquer les spectres produits par {sup 6}Li. On suppose que {sup 6}Li forme une molecule nucleaire avec la cible qui eclate ensuite de facon telle qu'une particule alpha de la molecule sort avec l'energie cinetique de son mouvement propre dans la molecule. Les spectres calcules avec ces hypotheses et les spectres mesures sont en bon accord. (auteur)

  5. Projet de classification de spectres stellaires IUE à basse résolution par système expert.

    Science.gov (United States)

    Imadache, A.

    Le project d'étude porte sur l'utilisation de l'intelligence artificielle en vue d'établir une classification de spectres IUE. Pour la réalisation de ce projet, des liens de collaboration ont été établis entre l'Observatoire Astronomique de Strasbourg et l'équipe ST-ECF à l'ESO.

  6. 76 Valorisation agricole des déchets comme alternative à leur ...

    African Journals Online (AJOL)

    User

    Valorisation agricole des déchets comme alternative à leur gestion dans les villes d'Afrique subsaharienne : caractérisation des déchets urbains à. Lubumbashi et évaluation de leurs effets sur la croissance des cultures vivrières. Louis BABOY LONGANZA1,2, Laurent KIDINDA KIDINDA1*,Dominique TSHIPAMA TAMINA3,.

  7. Valorisation agricole des déchets comme alternative à leur gestion ...

    African Journals Online (AJOL)

    Valorisation agricole des déchets comme alternative à leur gestion dans les villes d'Afrique subsaharienne : caractérisation des déchets urbains à Lubumbashi et évaluation de leurs effets sur la croissance des cultures vivrières.

  8. Some Measurements of Thermal Neutron Spectra; Mesure de Spectres de Neutrons Thermiques; Nekotorye izmereniya spektrov teplovykh nejtronov; Algunas Mediciones de Espectros de Neutrones Termicos

    Energy Technology Data Exchange (ETDEWEB)

    Poole, M. J.; Schofield, P.; Sinclair, R. N. [United Kingdom Atomic Energy Authority, Research Group, Atomic Energy Research Establishment, Harwell (United Kingdom)

    1964-04-15

    River scattering-law data, in an attempt to predict the shape of the energy spectrum at positions in both blocks. A second experiment introduces a spatial discontinuity instead of thermal. A disc of cadmium sufficiently thick to be black to all neutrons below 0.4 eV is fixed centrally in a tank of water and spectra have been measured near to the disc as a function both of position and of direction of travel of the neutrons (relative to the plane of the cadmium). Finally may be mentioned spectrum measurements in a graphite-uranium lartice which provide a check on spectrum calculations in reactor geometry. Many spectrum experiments can be carried out in either critical or subcritical geometry, and in some discussion is given of the relative merits of those two methods of approach. (author) [French] Les auteurs ont entrepris a Harwell l'execution de travaux complementaires pour determiner la loi de diffusion dans le ralentisseur et pour verifier la validite de cette loi en procedant a des mesures du spectre. La plupart des experiences sur la loi de diffusion ont ete faites a Chalk River (Canada); le traitement des donnees se fait au Laboratoire national d'Argonne (Etats-Unis), et l'analyse ainsi que l'extrapolation necessaire des resultats des mesures se font a Harwell. Les mesures du spectre se divisent naturellement en deux groupes. En utilisant la spectroscopie du temps de vol, les auteurs ont fait un grand nombre de mesures de spectres de neutrons thermiques dans des ralentisseurs empoisonnes homogenes. Ces travaux completent ceux qui ont deja ete effectues par les auteurs et par Beyster et al.; ils servent a verifier les valeurs des sections efficaces du transfert d'energie o(E -> E) deduites de la loi de diffusion en usage. Toutefois, cette experience n'est nullement sensible aux variations angulaires de la diffusion ni a la partie de la section efficace de diffusion qui ne comporte pas de changement de l'energie du neutron diffuse; or, ces deux facteurs ont leur

  9. Marcel Duchamp, Constantin Brancusi, Victor Brauner : leurs rencontres et les retombées sur leurs œuvres

    Directory of Open Access Journals (Sweden)

    Cristian-Robert Velescu

    2013-12-01

    Full Text Available Duchamp avait rencontré Brancusi en 1912, année qui marque le début d’une amitié consignée par l’histoire de l’art. Son parcours avait été fixé dans les pages de leur correspondance, conservées au Centre Georges Pompidou. Le lecteur est surpris de constater qu’il n’y a que des faits anodins qui soient consignés, tandis que les références aux conceptions artistiques sont presque totalement absentes. Toutefois, en lisant les témoignages de Duchamp conservés dans les célèbres Boîtes (verte et blanche, on se rend compte qu’il partage les conceptions platoniciennes de son ami sculpteur, chose importante, qui nous laisse formuler des suppositions concernant une influence dirigée de Brancusi dans la direction Duchamp. À son tour, durant l’intervalle 1925–1928, Victor Brauner était l’hôte de Brancusi dans l’atelier de l’impasse Ronsin. C’est ici qu’il a pu rencontrer Duchamp, qui s’y rendait fréquemment dans les années 20. Une rencontre qui a certainement eu des retombées sur l’oeuvre du futur peintre surréaliste. La preuve en est dans deux de ses toiles, Tête et deux boxeurs et Passivité courtoise. Faut-il s’étonner que le message que Duchamp avait mis dans les structures sémantiques de son chef-d’oeuvre La Mariée mise à nu par ses célibataires, même ou Le Grand Verre y avait été « logé » d’une manière évidente ? Mais alors on doit reconnaître que lors de leurs rencontres de chez Brancusi, Duchamp avait transmis à Brauner des informations très précises sur l’iconographie du Grand Verre, ainsi que sur la quatrième dimension, que le futur peintre surréaliste allait reconvertir dans les trois dimensions de l’espace ordinaire. Perçu dans cette perspective, l’atelier de l’impasse Ronsin nous semble un lieu où les idées des trois artistes ont pu communiquer d’une manière osmotique.

  10. Comparative study of the formation of fenchenes and of their N.M.R. spectra; Etude comparative de la formation des fenchenes et de leurs spectres de R.M.N

    Energy Technology Data Exchange (ETDEWEB)

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

    1970-01-01

    The dehydration of {alpha}-fenchyl alcohol and {alpha}-iso-fenchyl alcohol is studied in detail: two new techniques (chromatography on silica with silver nitrate, and nuclear magnetic resonance) permit to analyse the formation of various fenchenes and to achieve the synthesis of {alpha}- and {beta}-fenchenes. (author) [French] On etudie en detail la deshydratation de l'{alpha}-fenchol et de l'{alpha}-isofenchol: grace a l'utilisation de deux techniques nouvelles (chromatographie sur silice impregnee de nitrate d'argent et resonance magnetique nucleaire), on a pu analyser la formation des divers fenchenes. On met au point la preparation de l'{alpha}- et du {beta}-fenchenes. (auteur)

  11. Comparative study of the formation of fenchenes and of their N.M.R. spectra; Etude comparative de la formation des fenchenes et de leurs spectres de R.M.N

    Energy Technology Data Exchange (ETDEWEB)

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

    1970-01-01

    The dehydration of {alpha}-fenchyl alcohol and {alpha}-iso-fenchyl alcohol is studied in detail: two new techniques (chromatography on silica with silver nitrate, and nuclear magnetic resonance) permit to analyse the formation of various fenchenes and to achieve the synthesis of {alpha}- and {beta}-fenchenes. (author) [French] On etudie en detail la deshydratation de l'{alpha}-fenchol et de l'{alpha}-isofenchol: grace a l'utilisation de deux techniques nouvelles (chromatographie sur silice impregnee de nitrate d'argent et resonance magnetique nucleaire), on a pu analyser la formation des divers fenchenes. On met au point la preparation de l'{alpha}- et du {beta}-fenchenes. (auteur)

  12. D'éminents spécialistes mettent leur savoir-faire en commun | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    8 oct. 2010 ... Selon Nelson Sewankambo, beaucoup d'interventions ont fait leurs ... As the world observed International Youth Day (August 12), IDRC asked researchers: ... Under the International Research Chairs Initiative, top specialists ...

  13. Production of photons with a narrow energy spectrum, starting from high energy electrons; Production de photons de spectre etroit a partir d'electrons de grande energie

    Energy Technology Data Exchange (ETDEWEB)

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

    1958-07-01

    A method for the production of photons with a narrow spectrum and of variable energy, based on the properties of the annihilation in flight of positrons, is examined in detail. The spectra of the photons produced and the yield of the process are given for various conditions. (author) [French] Une methode de production de photons de spectre etroit et d'energie variable, basee sur les proprietes de l'annihilation en vol des positons, est examinee en detail. Le spectre des photons produits, le rendement du processus sont donnes pour diverses conditions. (auteur)

  14. Le rendement dans l’utilisation du clavier d’ordinateur pour écrire chez les personnes ayant un trouble du spectre de l’autisme / Performance using a computer keyboard for writing among persons with an autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Claire Dumont

    2015-03-01

    Full Text Available Les personnes ayant un trouble du spectre de l’autisme (TSA ont fréquemment des problèmes graphomoteurs. Ces difficultés ont à leur tour des répercussions sur de nombreuses occupations, le rendement scolaire et le développement de la personne. Dans cette situation, l’écriture avec un clavier peut s’avérer une alternative pertinente. Cette étude vise à décrire le rendement des enfants ayant un TSA dans leur réalisation de tâches avec le clavier d’ordinateur et de le comparer à celui des enfants à développement typique. Le Test du rendement dans l’utilisation de l’ordinateur a été administré à un échantillon de 53 enfants âgés entre six et 15 ans ayant un TSA. Les résultats suggèrent qu’ils peuvent avoir un rendement équivalent, supérieur ou inférieur en fonction de leurs caractéristiques et du type de tâche. Le test permet également d’observer plusieurs particularités de leurs processus d’apprentissage. Des suggestions pour l’amélioration des connaissances et des pratiques en découlent. Persons with an autism spectrum disorder (ASD frequently have graphomotor problems. These difficulties in turn have repercussions on numerous tasks, on academic performance and on personal development. In this situation, writing using a keyboard can be a relevant alternative. This study aims to describe the performance of children with an ASD in performing tasks using a computer keyboard and to compare it with that of children whose development is typical. The Performance using a computer test was administered to a sample of 53 children with an ASD, aged 6 to 15. Findings suggest that they can offer an equal, superior or inferior performance depending on their characteristics and on the type of task performed. The test also allows the observation of several characteristics in their learning processes. Suggestions for the improvement of the knowledge base and practices follow.

  15. Etude de la formation de resonances electroniques et de leur role dans la fragmentation neutre de molecules d'interet biologique

    Science.gov (United States)

    Lepage, Martin

    1998-12-01

    Cette these est presentee a la Faculte de medecine de l'Universite de Sherbrooke en vue de l'obtention du grade de Ph.D. en Radiobiologie. Elle contient des resultats experimentaux enregistres avec un spectrometre d'electrons a haute resolution. Ces resultats portent sur la formation de resonances electroniques en phase condensee et de differents canaux pour leur decroissance. En premier lieu, nous presentons des mesures d'excitations vibrationnelles de l'oxygene dilue en matrice d'argon pour des energies des electrons incidents de 1 a 20 eV. Les resultats suggerent que le temps de vie des resonances de l'oxygene est modifie par la densite d'etats d'electrons dans la bande de conduction de l'argon. Nous presentons aussi des spectres de pertes d'energie d'electrons des molecules de tetrahydrofuranne (THF) et d'acetone. Dans les deux cas, la position en energie des pertes associees aux excitations vibrationnelles est en excellent accord avec les resultats trouves dans la litterature. Les fonctions d'excitation de ces modes revelent la presence de plusieurs nouvelles resonances electroniques. Nous comparons les resonances du THF et celles de la molecule de cyclopentane en phase gazeuse. Nous proposons une origine commune aux resonances ce qui implique qu'elles ne sont pas necessairement attribuees a l'excitation des electrons non-apparies de l'oxygene du THF. Nous proposons une nouvelle methode basee sur la spectroscopie par pertes d'energie des electrons pour detecter la production de fragments neutres qui demeurent a l'interieur d'un film mince condense a basse temperature. Cette methode se base sur la detection des excitations electroniques du produit neutre. Nous presentons des resultats de la production de CO dans un film de methanol. Le taux de production de CO en fonction de l'energie incidente des electrons est calibre en termes d'une section efficace totale de diffusion des electrons. Les resultats indiquent une augmentation lineaire du taux de production de

  16. Rattachement hiérachique du contrôleur de gestion, perception du contrôle de gestion et qualité des relations contrôleurs - manageurs : une étude exploratoire

    OpenAIRE

    Armelle Godener; Marianela Fornerino

    2004-01-01

    Working paper serie RMT (WPS 04-02); La recherche proposée étudie le lien existant entre le rattachement hiérarchique du contrôleur de gestion et la perception du contrôle de gestion par les directeurs de l'entité pour laquelle travaille le contrôleur ainsi que par les opérationnels, ainsi que le lien rattachant cette perception et la qualité des relations contrôleurs / directeurs et contrôleurs / opérationn

  17. OCaLustre : une extension synchrone d'OCaml pour la programmation de microcontrôleurs

    OpenAIRE

    Varoumas , Steven; Vaugon , Benoît; Chailloux , Emmanuel

    2017-01-01

    International audience; Les microcontrôleurs sont des circuits intégrés programmables dont le domaine d'application se concentre essentiellement dans le contrôle d'objets interagissant avec leur environnement. En effet, les programmes exécutés sur microcontrôleurs ont souvent pour rôle de réagir rapidement avec les composants qui les entourent, et de modifier leurs signaux de sortie dès lors que les signaux qu'ils reçoivent en entrée changent. Ainsi, la programmation synchrone à flots de donn...

  18. L’utilisation d’internet par les parents d’enfants ayant un trouble du spectre de l’autisme / Internet use by parents of children with autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Georgette Goupil

    2014-05-01

    Full Text Available Le WEB représente une source importante d’information en matière de santé ou de déficience. Toutefois, peu d'études décrivent la fréquence d'utilisation d'Internet et les données consultées par les parents d’enfants qui ont un ont trouble du spectre de l’autisme (TSA. Cette étude a pour objectif de décrire la fréquence et la durée des recherches de ces parents sur Internet, les sites et le type d'information consultée en ligne, leurs perceptions de l'utilité de l'information et de son effet sur l’anxiété. Cent vingt-trois parents d'enfants ayant un TSA ont rempli un questionnaire d'enquête. Parmi les participants, 90% utilisent Internet pour recueillir des informations sur les TSA. Les données indiquent une fréquence d’utilisation élevée, plus grande que celle en général observée auprès de la population en matière de santé. Les mères consultent plus que les pères et il y a une relation positive entre la récence du diagnostic et la fréquence des consultations. Il y a peu de différence dans les perceptions des parents sur l’utilité entre les sites, tous étant jugés utiles ou très utiles. La discussion soulève la question de la discrimination par les parents de la qualité de l’information et des effets des recherches sur leurs choix d’intervention. The Web is an important source of information on health and disability; however, few studies describe the frequency of Internet use and the data accessed by the parents of children who have autism spectrum disorders (ASD. The objective of this study is to describe the frequency and duration of the online research conducted by these parents, the Internet sites and the type of information available online, parents’ perceptions of the usefulness of the information and its effect on anxiety. 123 parents of children with ASD completed a questionnaire. Among the participants, 90% used the Internet to find information about ASD. The data indicate higher

  19. Accès aux TIC et leur utilisation en enseignement supérieur en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les politiques dans le domaine de l'enseignement supérieur en matière de technologies de l'information et de la communication (TIC) présument qu'un accès accru aux TIC encourage leur utilisation. Une première collecte de données effectuée en 2004 et 2007 fournit une base des plus nécessaires sur laquelle fonder la ...

  20. Évaluation des teneurs sériques en sodium et en calcium et de leurs ...

    African Journals Online (AJOL)

    Méthodologie et résultats: Cette recherche a été menée sur 45 sérums dont 15 provenant de chèvres gestantes (Gg), 15 de leurs placentas (Pg) et 15 de leurs foetus (Fg) abattues dans les tueries du marché mzee Kabila à Lubumbashi. Les teneurs sodiques et calciques ont été obtenues au spectrophotomètre par dosage ...

  1. Symetrie en energie des spectres de l'onde de densite de charge dans le 2-hydrogene seleniure de niobium

    Science.gov (United States)

    Behmand, Behnaz

    Les mecanismes qui menent a la supraconductivite dans les supraconducteurs a haute temperature critique sont encore aujourd'hui mal compris contrairement a ceux dans les supraconducteurs conventionnels. Dans les hauts-Tc, certaines modulations de la densite d'etats electroniques coexistant avec la phase supraconductrice ont ete observees, ce qui engendre des questionnements sur leur role dans la supraconductivite. En fait, plusieurs types de modulation de la densite d'etats electroniques existent, comme par exemple l'onde de densite de charge et l'onde de densite de paires. Ces deux modulations, d'origines differentes et mesurables avec la technique de spectroscopie par effet tunnel, peuvent etre differenciees avec une etude de leur symetrie. Ce memoire consistera donc a presenter l'etude de la symetrie de l'onde de densite de charge dans le 2H-NbSe2 qui est presente dans la phase supraconductrice a 300 mK. Par contre, certaines difficultes liees au principe de mesure, soit l'effet de normalisation, nuisent a l'identification de cette symetrie. La methode, pour contourner ce probleme sera alors l'element clef de ce travail.

  2. Spectra theory for nuclei with closed shells (1962); Theorie des spectres des noyaux a couches completes (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-07-01

    second approximation which alone leads to a region of optimum agreement identical for both carbon and oxygen. An excellent general agreement is obtained with the known spectra of these two nuclei. The importance of higher order terms in the calculation of the 3{sup -} and 5{sup -} collective states for calcium 40 is demonstrated; furthermore it is possible to explain these levels only by the second approximation. Certain forecasts are made using the effective forces thus found. (author) [French] On applique une theorie unifiee des spectres des noyaux a couches completes, fondee sur les excitations elementaires particule-trou de ces systemes, a l'etude du carbone 12, de l'oxygene i6 et du calcium.40. Deux approximations sont utilisees. La premiere consiste a diagonaliser l'interaction residuelle a deux corps dans un sous-espace limite de configurations a une particule et un trou. Sa validite repose sur l'energie importante exigee pour l'excitation d'une paire particule-trou. La seconde approximation consiste a resommer la sous-serie infinie des diagrammes particule-trou. Elle est equivalente a la methode de Hartree-Fock dependante du temps ou a la methode des Quasi-Bosons. Son domaine de validite, dans le cas nucleaire, n'est pas bien compris. Les diagrammes sommes sont preponderants a la limite des fortes densites, alors que la densite nucleaire est de l'ordre de l'unite. La violation des Principe de Pauli, dans cette approximation, n'est justifiee que si le nombre de paires excitees est petit par rapport au nombre d'etats de particule disponibles; or, dans les noyaux legers les degenerescences des couches sont petites. Neanmoins cette approximation qui postule l'existence d'un champ nucleaire moyen, lentement variable dans le temps par rapport aux periodes des nucleons a le merite d'etre self-consistante, de donner des etats propres orthogonaux a l'etat non physique du centre de masse et d'ameliorer le calcul des regles de somme. Pour determiner et limiter le role de la

  3. Les différences culturelles et leur impact sur la relation soignant-soigné

    OpenAIRE

    Uysal, Ayse; Matter, Catherine

    2011-01-01

    Ce travail porte sur les différences culturelles et leur impact sur la relation soignant-soigné lors d’une hospitalisation. Ainsi la problématique de recherche est centrée sur l’identification des difficultés et des spécificités présentes lorsque le soignant entre en relation avec un patient d’une culture différente. Le but de cette étude est d’identifier les difficultés et les obstacles liés à la culture, présents dans la relation soignant-soigné. Le deuxième but est de mettre en évidence le...

  4. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  5. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  6. 'The Public Spectre'

    DEFF Research Database (Denmark)

    Jepsen, Kim Sune Karrasch; Bertilsson, Margareta; Delgado, Ana

    2016-01-01

    This paper is concerned with how forms of publics come into being in situations of technological innovation and change. The paper attends to sudden social formations which arise as responses to what is perceived of as threatening socio-technical inventions into the routine of everyday social life....... We revisit the Dewey-Lippmann debate, and we look at spontaneous citizens’ reactions towards emerging technologies such as Google Street View as well as we discuss some institutionally organized events of public engagement with science. As we explore the formation of publics inside and outside...

  7. Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

  8. Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

  9. Application of statistical methods to the treatment of a composite spectrum; Application de methodes statistiques a l'exploitation d'un spectre d'ensemble

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    A study has been made of: - on the one hand the possibility of improving the {gamma}-neutron discrimination of a direct-current ionisation chamber using as the signal not the mean value but the variance of the detector's exit current. - on the other hand, the possibility of concentrating all the information contained in a simple spectrum made up of Gaussian curves into a small number of variables. (author) [French] On etudie: - d'une part, la possibilite d'ameliorer la discrimination neutrons {gamma} dans une chambre d'ionisation a courant continu, en utilisant comme signal, non pas la valeur moyenne mais la variance du courant de sortie du detecteur. - d'autre part, la possibilite de concentrer toute l'information contenue dans un spectre simple compose de courbes de Gauss, en un nombre reduit de donnees. (auteur)

  10. Some considerations of the energy spectrum of odd-odd deformed nuclei; Quelqes considerations sur le spectre d'energie des noyaux impair-impair deformes

    Energy Technology Data Exchange (ETDEWEB)

    Alceanu-G, Pinho de; Picard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The odd-odd deformed nuclei are described as a rotator plus two odd nucleons moving in orbitals {omega}{sub p} and {omega}{sub n} of the deformed potential. We investigate the energies and wave functions of the various states of the ({omega}{sub p}, {omega}{sub n}) configurations by calculating and numerically diagonalizing the Hamiltonian matrix (with R.P.C. and residual interactions). The Gallagher-Mosskowski coupling rules ana the abnormal K equals 0 rotational bands are discussed. (authors) [French] Les noyaux impair-impairs deformes sont decrits comme un rotateur plus deux nucleons non apparies dans les orbites {omega}{sub p} et {omega}{sub n} du potentiel deforme. Nous etudions le spectre d'energie et les fonctions d'onde des configurations ({omega}{sub p}, {omega}{sub n}) en tenant compte de l'interaction particule-rotation et de la force residuelle entre les deux nucleons celibataires.

  11. Comets in UV

    Science.gov (United States)

    Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

    2018-04-01

    Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

  12. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

    There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

  13. UV-induced effects

    NARCIS (Netherlands)

    Liebsch, M.; Spielmann, H.; Pape, W.; Krul, C.; Deguercy, A.; Eskes, C.A.M.

    2005-01-01

    Regulatory requirements: According to the current Notes for Guidance of the Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP), cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light

  14. Calculation of {psi}, {phi} and of their derivatives; calcul de {psi}, {phi} et de leurs derivees

    Energy Technology Data Exchange (ETDEWEB)

    Dandeu, Y; Gautier, L; Guillermin, J; Olivie, G; Roche, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The functions: {psi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}{sub -{infinity}}{sup +{infinity}} [e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dx and {phi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}-{infinity}+{infinity} [y e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dy as well as their primary and secondary derivatives with respect to x and {beta} have been calculated for the whole of the (x,{beta}) plane using a certain number of different methods: series development, asymptotic development, Hermites polynomials and approximating formulae. These methods have made it possible to conserve a constant relative accuracy, except in the neighbourhood of the regions where the derivatives disappear. (authors) [French] Les fonctions: {psi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}{sub -{infinity}}{sup +{infinity}} [e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dx and {phi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}-{infinity}+{infinity} [y e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dy ainsi que leurs derivees premieres et secondes par rapport a x et a {beta} ont pu etre calculees dans tout le plan (x,{beta}) en faisant appel a un certain nombre de methodes differentes: developpement en serie, developpement asymptotique, polynomes d'Hermites, et formules approchees. Ces methodes ont permis de conserver une precision relative constante, sauf au voisinage des zones d'annulation des derivees. (auteurs)

  15. artographie des risques naturels dans les Pyrénées et sur leur piémont

    Directory of Open Access Journals (Sweden)

    Jean-Marc ANTOINE

    1994-12-01

    Full Text Available Les recherches menées par le CIMA URA-366 sur les risques naturels dans les Pyrénées privilégient leur dimension historique et l’étude des contextes socio-écologiques dans lesquels ils s’inscrivent. Cette approche novatrice débouche sur une cartographie historique des phénomènes, conjugant plusieurs niveaux d’analyse spatiotemporels.

  16. Reactor AQUILON. The hardening of neutron spectrum in natural uranium rods, with a computation of epithermal fissions (1961); Pile AQUILON. Durcissement du spectre des neutrons dans les barreaux d'uranium et calcul des fissions epithermiques (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Durand -Smet, R; Lourme, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    - Microscopic flux measurements in reactor Aquilon have allowed to investigate the thermal and epithermal flux distribution in natural uranium rods, then to obtain the neutron spectrum variations in uranium, Wescott '{beta}' term of the average spectrum in the rod, and the ratio of epithermal to therma fissions. A new definition for the infinite multiplication factor is proposed in annex, which takes into account epithermal parameters. (authors) [French] - Un certain nombre de mesures effectuees dans la pile Aquilon ont permis d'etablir la distribution fine des flux thermique et epithermique dans les barreaux d'uranium, et d'en deduire les variations du spectre des neutrons dans l'uranium, le terme {beta} du spectre de Wescott moyen dans le barreau et le nombre de fissions epithermiques. En annexe, il est propose une definition nouvelle du coefficient de multiplication infini, qui fait intervenir les parametres epithermiques. (auteurs)

  17. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  18. Les guides européens et leurs auteurs : clefs de lecture

    Directory of Open Access Journals (Sweden)

    Goulven Guilcher

    2011-12-01

    Full Text Available Après avoir expliqué comment se constitue une collection de guides en relation avec une recherche universitaire, cette contribution décrit le contexte d’apparition des trois grandes collections européennes de guides du XIXe siècle : Murray, Baedeker et Joanne. À travers une analyse comparative très fine, Goulven Guilcher montre ce qui fait leur spécificité et ce qui les distingue. Il s’intéresse aussi à la place que laissent ces collections à d’autres types de guides, à l’influence qu’exercent les auteurs de guides et directeurs de collections sur le contenu de ces publications. L’œil attentif du spécialiste décèle la manière dont les guides de voyage rendent compte des pratiques et des usages touristiques à travers les conseils fournis et les publicités. Le bibliophile, quant à lui, apprécie les cartes et les gravures dont se dotent les guides pour donner à voir les territoires décrits.After explaining how a collection of guides is built up in connection with research at university level this article studies the genesis of the main three european collections of guidebooks in the XIXth century: Murray, Baedeker and Joanne-Hachette. By means of a detailed comparative analysis GoulvenGuilcher describes the features that characterize them. He also deals with the room left by these collections for other types of guides and the influence exerted by the authors of the guides and the heads of collections over the contents of these publications. By close scrutiny the specialist is able to determine in what way guidebooks take into account the uses of tourism, at the same time by means of advice to travellers and through advertisements. The bibliophile assesses maps and illustrations offeredin the guides in order to give an image of the countries they describe.

  19. Some considerations of the energy spectrum of odd-odd deformed nuclei; Quelqes considerations sur le spectre d'energie des noyaux impair-impair deformes

    Energy Technology Data Exchange (ETDEWEB)

    Alceanu-G, Pinho de; Picard, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The odd-odd deformed nuclei are described as a rotator plus two odd nucleons moving in orbitals {omega}{sub p} and {omega}{sub n} of the deformed potential. We investigate the energies and wave functions of the various states of the ({omega}{sub p}, {omega}{sub n}) configurations by calculating and numerically diagonalizing the Hamiltonian matrix (with R.P.C. and residual interactions). The Gallagher-Mosskowski coupling rules ana the abnormal K equals 0 rotational bands are discussed. (authors) [French] Les noyaux impair-impairs deformes sont decrits comme un rotateur plus deux nucleons non apparies dans les orbites {omega}{sub p} et {omega}{sub n} du potentiel deforme. Nous etudions le spectre d'energie et les fonctions d'onde des configurations ({omega}{sub p}, {omega}{sub n}) en tenant compte de l'interaction particule-rotation et de la force residuelle entre les deux nucleons celibataires.

  20. Results and interpretation of spectral indices measurements made with AQUILON; Resultats et interpretation de mesures d'indices de spectre dans aquilon

    Energy Technology Data Exchange (ETDEWEB)

    Frichet, J P; Mougey, J N; Naudet, R; Taste, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    This report deals with a set of spectral indices measurements made in the heavy water reactor Aquilon on lattices constituted by massive fuel elements of dia. 29,2 mm. The fuel elements were made either of natural uranium or of slightly depleted or slightly enriched uranium, or of an uranium-plutonium alloy. The measurements were carried out for various lattice pitches (square pitch from 110 to 210 mm) and in certain cases for various temperatures (from 20 to 80 deg. C). The results are compared to calculated values obtained by using the latest advances of the thermalization theory developed at Saclay applied to the moderation by heavy water. (authors) [French] Ce rapport est consacre a un ensemble de mesures d'indices de spectre realisees dans la pile a eau lourde Aquilon sur des reseaux d'elements combustibles pleins, de 29,2 mm de diametre. Ces combustibles se composaient ou bien d'uranium naturel, ou bien d'uranium tres legerement appauvri ou enrichi, ou bien d'un alliage uranium plutonium. Les mesures ont ete effectuees pour toute une serie de pas de reseaux (pas carre 110 a 210 mm), certaines d'entre elles a plusieurs temperatures (20 a 80 deg. C). Les resultats des mesures sont compares a des valeurs calculees obtenues en utilisant les plus recents developpements de la theorie de la thermalisation mise au point a Saclay, appliques au cas de la moderation par l'eau lourde. (auteurs)

  1. Study of the influence of the fast neutron spectrum on the production of defects in solids and liquids; Etude de l'influence du spectre des neutrons rapides sur la creation de defauts dans les solides et les liquides

    Energy Technology Data Exchange (ETDEWEB)

    Mas, P; Droulers, Y [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-07-01

    In the first part of this work a calculation has been made of the number of defects formed in graphite by a given neutron flux having various spectral distributions. The defect formation function is that of KINCHIN and PEASE; its formulation is briefly given. An efficiency function is then defined for a fast neutron spectrum. This defects produced in a light water reactor and those produced in a graphite reactor. Finally an application of this method is given for comparing the defect forming tendency in graphite in the case of the reactor Melusine and of the reactor G-2 and G-3. In the second part are calculated the integrals for the energy release brought about by fast neutrons in carbon oxygen and hydrogen. In a region of 25 cm around the core of a swimming-pool type reactor these energy release integrals are approximately proportional to the neutron flux above 1 MeV. The determination of the energy released as a result of the passage of neutrons in organic liquids can therefore be reduced to the measurement of the flux above 1 MeV for the real spectral distribution. A calorimetric verification has been carried out in the case of water. (authors) [French] Dans la premiere partie de cette etude, on a calcule le nombre de defauts crees dans le graphite par un flux de neutrons donne, pris sous differents spectres. On a ainsi fait les calculs pour 4 spectres de pile. piscine et 2 spectres de pile au graphite. La fonction creation de defauts est celle de KINCHIN et PEASE. On rappelle brievement sa formulation. Puis on definit une fonction efficacite d'un spectre de neutrons rapides. Cette fonction permet alors d'etablir la relation entre defauts crees dans une pile a eau legere et defauts crees dans une pile au graphite. Enfin, une application de cette methode est donnee pour comparer l'aptitude a creer les defauts dans le graphite par la pile MELUSINE et les piles G-2 ou G-3. Dans la deuxieme partie, on a calcule les integrales de degagement d'energie provoque par

  2. The Nature of the Phonon Spectrum and the Analysis of Lattice Thermal Conductivity; Nature du Spectre des Phonons et Analyse de la Conductibilite Thermique du Reseau; Kharakter fononnogo spektra i analiz teploprovodnosti reshetki; Naturaleza del Espectro Fononico y Analisis de la Conductividad Termica Reticular

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S. K.; Sharma, K. C. [Physics Department, Allahabad University, Allahabad (India)

    1965-04-15

    auteurs presentent les resultats d'une etude sur la conductibilite thermique des reseaux effectuee au moyen d'un spectre de phonons plus precis que le spectre de phonons analogue au modele de Debye, utilise d'ordinaire, qui est constitue par une seule branche acoustique moyenne. Pour calculer les variations en fonction de la temperature de la conductibilite thermique du reseau du germanium, ils ont utilise tout d'abord un modele anisotrope de dispersion en continu et suivi comme methode une version modifiee de la formulation de Callaway. Pour effectuer la sommation d'integrales complexes sur les frequences du reseau, ils ont applique la methode d'integration a six et trois termes de Houston. On utilise les expressions appropriees des temps de relaxation pour les diffusions a la frontiere et les diffusions dues aux impuretes ainsi que pour le processus normal a trois phonons et le processus Umklapp. Pour le germanium entre 2 et 1000 Degree-Sign K, on obtient une concordance satisfaisante avec les donnees experimentales de Holland et de Slack et Glassbrenner en ajustant les quatre constantes presentes dans les integrales. D'apres des donnees de spectroscopie des neutrons dignes de foi, on sait que le germanium comporte des branches transversales tres dispersees et qu'un modele anisotrope de dispersion en continu en donne aussi une mauvaise representation. Les auteurs ont donc juge bon d'utiliser le modele des couches tres complexes pour la dynamique de reseau du germanium presente pai Cochran. En ajustant les parametres entrant dans la formulation qu'ils ont utilisee pour le calcul de la conductibilite thermique du reseau, ils ont egalement obtenu des resultats concordant avec les donnees experimentales. Ceci leur a donne a penser que la nature du spectre des phonons n'a pas une grande influence sur l'analyse des donnees relatives a la conductibilite thermique du reseau suivant les methodes actuelles, et que le spectre des phonons perd de sa precision en raison de l

  3. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

    Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

  4. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

    The use of synchrotron radiation (SR) in the ultraviolet (UV) region by biophysics and biophysical chemists continues to increase as access improves and as awareness of its unique combination of properties grows. SR is continuously tunable, intense (even in the UV region), and pulsed. Pulse characteristics are comparable to those of picosecond lasers, but have the advantage of being independent of wavelength. Drawbacks are the continuous, but slow, decay of intensity arising from loss of particles in the ring, and the intrinsic limitation in pulse repetition rate. The particular combination of features that makes SR a superior light source depends upon the application. Spectroscopic techniques based on absorption and some techniques based on emission exploit its intensity and continuous tunability; time resolved techniques make use of its pulse characteristics. This chapter is a status report on two of the major biological applications of UV SR, circular dichroism and time-resolved fluorescence, covering mainly the published literature of the last five years. For the present purpose, the term UV is understood to include the vacuum ultraviolet region to 100 nm. (author). 83 refs.; 4 figs.; 6 tabs

  5. Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

    NARCIS (Netherlands)

    Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

    2016-01-01

    Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

  6. Experimental measurement of neutron spectrum in the reflector of a light water reactor; Determination experimentale du spectre des neutrons dans le reflecteur d'une pile a eau legere

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-09-15

    1. Thermal neutrons: The temperature of the thermal neutron spectrum was calculated using Au-Lu foils. This temperature varies from 300 deg. K (temperature of the moderator) at 30 cm of the core to 350 deg. K in a hole of the core. 2. Slowing down of neutron: Four resonance detectors have been used (Au, In, Co, Mn). We can write a 1/E form of the spectrum. The linking up energy E{sub M} between thermal neutron spectrum and slowing down spectrum is about 0.23 eV and is free from the Maxwell spectrum temperature. The decrease of slowing down flux regarding thermal flux, farther from the core, has been showed. 3. Fast neutrons: We used 3 threshold detectors (Ni, Al, Mg). We supposed a E{sup 1/2} e{sup -{beta}}{sup E} from of the spectrum above 3 MeV. The values of {beta} are in a range from 0.775, at the centre of the core and in a loop-hole, to 0,64 at about 30 cm of the core. 4. Continuous shape of the spectrum: The following interpolations give useful informations between the field where measurements have been made: between 340 eV and 10 keV: 1/E form between 10 keV and 330 keV: 1/(E {sigma}{sub S}(E)) form ({sigma}{sub S}(E) elastic scattering section on hydrogen) between 330 keV and 3 MeV: calculated form by the moments method (ref. BSR). (author) [French] 1. Neutrons thermiques: La temperature du spectre des neutrons thermiques a ete determinee par la methode (or-lutecium). Cette temperature varie de 300 deg. K (temperature du moderateur) a 30 cm du coeur, a 350 deg. K dans une encoche du coeur. 2. Neutrons en ralentissement: 4 detecteurs resonnants ont ete employes (Au, In, Co, Mn). Le spectre peut etre mis sous la forme 1/E quelle que soit la distance a la limite coeur-reflecteur. L'energie de raccordement E{sub M} entre spectre des neutrons thermiques et spectre en ralentissement est environ 0,23 eV et independante de la temperature du spectre de Maxwell. La diminution relative du flux en ralentissement par rapport au flux thermique quand la distance au coeur

  7. Standardization of UV LED measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Larason, T. C.; Yoon, H. W.

    2015-09-01

    Traditionally used source spectral-distribution or detector spectral-response based standards cannot be applied for accurate UV LED measurements. Since the CIE standardized rectangular-shape spectral response function for UV measurements cannot be realized with small spectral mismatch when using filtered detectors, the UV measurement errors can be several times ten percent or larger. The UV LEDs produce broadband radiation and both their peaks or spectral bandwidths can change significantly. The detectors used for the measurement of these LEDs also have different spectral bandwidths. In the discussed example, where LEDs with 365 nm peak are applied for fluorescent crack-recognition using liquid penetrant (non-destructive) inspection, the broadband radiometric LED (signal) measurement procedure is standardized. A UV LED irradiance-source was calibrated against an FEL lamp standard to determine its spectral irradiance. The spectral irradiance responsivity of a reference UV meter was also calibrated. The output signal of the reference UV meter was calculated from the spectral irradiance of the UV source and the spectral irradiance responsivity of the reference UV meter. From the output signal, both the integrated irradiance (in the reference plane of the reference meter) and the integrated responsivity of the reference meter were determined. Test UV meters calibrated for integrated responsivity against the reference UV meter, can be used to determine the integrated irradiance from a field UV source. The obtained 5 % (k=2) measurement uncertainty can be decreased when meters with spectral response close to a constant value are selected.

  8. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

    The author describes the effects and health risks of UV exposure. This includes UV effects on the DNS, the eyes, the immune system, and the skin. Finally, recommendations are given for protection against excessive UV exposure on the basis of the IRPA/INIRC guidelines. (orig.) [de

  9. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-01-01

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium's UV FEL

  10. Measurements of the Asymptotic Spectrum of a Multiplying Medium; Mesures du Spectre Asymptotique d'Un Milieu Multiplicateur; Izmereniya asimptoticheskogo spektra umnozhayushchej sredy; Mediciones del Espectro Asintotico en un Medio Multiplicador

    Energy Technology Data Exchange (ETDEWEB)

    Slovacek, R. E.; Cerbone, R. J.; Gaerttner, E. R.; Fullwood, R. R.; Bach, D. R. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1965-08-15

    measurements have also been obtained in one of the assemblies to compare the two techniques using the same spectrometer. These results are still being analysed. As the asymptotic neutron density has a persistent spatial distribution which is more amenable to analysis, the asymptotic technique applied to multiplying systems should be extremely useful for studying the space-dependent spectrum problem over a large energy range. (author) [French] Le spectre asymptotique (dans le temps) d'un milieu multiplicateur presente un interet non seulement pour l'analyse des experiences au moyen des neutrons puises, mais egalement dans la recherche sur les proprietes du milieu concernant la diff- fusion des neutrons. Les auteurs ont mis au point la methode utilisant une source de neutrons puises et un hacheur mecanique de maniere a pouvoir mesurer le spectre aymptotique des neutrons dans un assemblage multiplicateur. Ils ont mesure les spectres a la surface et au centre (scalaire) pour 4 assemblages multiplicateurs et ils ont compare les resultats a ceux-des calculs. Tous les systemes multiplicateurs contenaient {sup 235}U enrichi et de l'hydrogene comme ralentisseur. Deux de ces assemblages etaient construits avec des lames de combustible gainees de zirconium, immergees dans l'eau; les deux autres assemblages etaient constitues par une dispersion de poudres de UO{sub 2} et de ZrO{sub 2} dans de la paraffine. Les auteurs ont choisi des dimensions et des rapports H/{sup 235}U differents de maniere a faire varier l'absorption, la fuite et la diffusion. Les auteurs ont calcule le spectre scalaire par la theorie de la diffusion a Petat stationnaire. Ils ont constate que les spectres mesures et les spectres scalaires etaient en bon accord s'ils utilisaient la valeur mesuree de la constante de decroissance asymptotique pour calculer le spectre. Il s 'est avere que le spectre asymp- totique calcule etait extremement sensible a la constante de decroissance; une variation de 7% de cette constante

  11. Chemical and UV Mutagenesis.

    Science.gov (United States)

    Bose, Jeffrey L

    2016-01-01

    The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

  12. UV curable materials development

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.G.

    1996-12-01

    Adhesives, coatings, and inks were selected for evaluation based on literature search and possible production applications. A differential photocalorimeter was used to measure degree of cure and allow prediction of optimum processing conditions. UV cure equipment were characterized and the ability to size equipment to specific materials cure needs established. Adhesion tests procedures were developed for the adhesives and solvent resistance testing procedures developed for the coatings and inks.

  13. Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras

    Energy Technology Data Exchange (ETDEWEB)

    DeHaan, A. Jr.; Leventhal, L.; Benson, P. [Tracerlab, Richmond, CA (United States)

    1965-10-15

    analysis. Statistical estimates for the errors in the resulting concentration of the radionuclides are provided for each analytical method when they are applied to multicomponent radionuclide mixtures. (author) [French] La resolution du rayonnement de melanges oomplexes d'emetteurs gamma a ete facilitee par l'emploi de spectrometres gamma tres perfectionnes et de calculatrices numeriques. Ces appareils sont maintenant a la disposition de presque tousles laboratoires techniques. Les auteurs etudient les techniques utilisees dans leur laboratoire pour mesurer les concentrations individuelles de differents radionucleides emetteurs gamma dans des echantillons provenant de retombees radioactives et comparent les resultats obtenus par les differentes methodes mathematiques avec des echantillons de composition complexe. Les donnees fournies par l'ordinateur sont comparees avec les resultats obtenus par analyse radiochimique de l'echantillon. Apres avoir analyse des composes binaires au moyen des methodes decrites ci-apres, les auteurs ont etendu l'analyse aux emetteurs composes de nombreux elements. Ils ont mis au point une methode avec ordinateur qui normalise les spectres gamma de maniere a reduire au minimum le glissement a long terme du spectrometre et qui convertit le spectre en une configuration dont l'energie est l'une des coordonnees. Ils etudient par les diverses methodes ci-apres les effets d'un 'pic photoelectrique imprevu ', d'un element d'intensitezero et de la superposition de pics, en particulier dans le cas d'echantillons de faible activite. Les auteurs ont analyse les methodes mathematiques les plus courantes pour la resolution des diverses composantes d'un spectre gamma complexe. La plupart de ces methodes aboutissent a une evaluation des concentrations de differents emetteurs gamma par l'un des procedes suivants: 1. Elimination successive des radionucleides a pic photoelectrique de forte energie, le spectre pur etant extrait du spectre compose jusqu

  14. Les biofilms bactériens : leur importance en santé animale et en santé publique

    OpenAIRE

    Tremblay, Yannick D.N.; Hathroubi, Skander; Jacques, Mario

    2014-01-01

    Les biofilms bactériens sont des amas structurés de cellules bactériennes enrobés d’une matrice polymérique et attachés à une surface. Le biofilm protège les bactéries et leur permet de survivre dans des conditions environnementales hostiles. Les bactéries du biofilm peuvent résister à la réponse immunitaire de l’hôte et sont beaucoup plus résistantes aux antibiotiques et aux désinfectants que les cellules bactériennes planctoniques. La capacité de former un biofilm est maintenant reconnue co...

  15. Les besoins en oxygène des poissons marins et leur comportement en conditions hypoxiques (revue bibliographique)

    OpenAIRE

    Person-le Ruyet, Jeanine

    1986-01-01

    Les données expérimentales relatives aux besoins en oxygène des poissons marins (pélagiques et démersaux) sont rappelées. Les variations de la consommation d'oxygène en fonction du poids (w) sont généralement décrites par l'équation : M02 (ml/h) = 0,33 W0. 80 Le comportement général des poissons en conditions hypoxiques et leurs limites de tolérance sont de même considérés en fonction du stade de développement.

  16. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

    Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

  17. Methods for determining fast neutron spectra using threshold detectors; Les methodes de determination des spectres de neutrons rapides a l'aide de detecteurs a seuil

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-07-01

    We propose to examine all the methods by which fast neutron spectra can be determined using the response of threshold detectors (activation or fission chamber detectors). Most of these methods have been proposed and often even used by various authors of which a list will be found in the bibliography. The aim of the present report is thus not to present original work but rather to gather into a single article and to present in a rational form a whole series of methods which have already been described in articles scattered throughout the specialised literature. Up to the present, each author has in general studied one or two methods and no comparative study of all the possible methods seems to have been made. The most comprehensive study on this topic is that of P.M. UTHE from whose article much has been borrowed. We have tried here to develop a useful tool which should facilitate the systematic experimental study leading to the recognition of the respective merits of the methods proposed. (author) [French] On se propose d'examiner l'ensemble des methodes permettant de determiner les spectres de neutrons rapides a partir des reponses de detecteurs a seuil (detecteurs par activation ou chambre a fission). La plupart de ces methodes ont deja ete proposees, et souvent meme utilisees, par differents auteurs dont on trouvera la liste en bibliographie. Le but du present rapport n'est donc pas de faire oeuvre originale mais plutot de rassembler dans un meme document et de presenter de maniere homogene toute une serie de methodes qui ont deja fait l'objet d'articles disperses dans la litterature specialisee. Jusqu'a present, chaque auteur s'est en general limite a l'etude experimentale d'une ou deux methodes et aucune etude comparative de l'ensemble des methodes possibles ne semble avoir ete faite. Le rapport le plus complet a ce sujet est celui de P.M. UTHE auquel de larges emprunts ont ete faits. On s'est efforce ici d'elaborer un outil de travail commode qui devrait

  18. uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

    Science.gov (United States)

    Chae, S K; Kafer, E

    1993-01-01

    Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

  19. Uvs Nuur, Mongolia

    Science.gov (United States)

    2007-01-01

    The Uvs Nuur Basin in Mongolia and the Russian Federation is the northernmost of the enclosed basins of Central Asia. It takes its name from Uvs Nuur Lake, a large, shallow and very saline lake, very important for migrating birds. Inscribed as a UNESCO World Heritage Site in 2003, the site is made up of twelve protected areas representing major biomes of eastern Eurasia. The steppe ecosystem supports a rich diversity of birds and the desert is home to a number of rare gerbil, jerboas and the marbled polecat. The mountains are an important refuge for the endangered snow leopard, mountain sheep, and the Asiatic ibex. The image covers an area of 46 x 47.8 km, was acquired on September 4, 2001, and is located near 50.3 degrees north latitude, 90.7 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  20. CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

    Science.gov (United States)

    Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

    2017-09-01

    Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

  1. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  2. Estimation de la survie des alevins de carpe (C. carpio au cours de leur premier mois d'existence

    Directory of Open Access Journals (Sweden)

    MOREAU J.

    1979-10-01

    Full Text Available Des observations réalisées sur deux stations piscicoles de Madagascar, dans des étangs ne recevant ni engrais ni nourriture, révèlent qu'au cours de leur premier mois les alevins de carpe (C. carpio subissent des mortalités voi-sines de 50 %. Ces dernières sont encore plus élevées en début et en fin de saison de reproduction. Au début, les fortes mortalités sont dues à la température trop basse et aux disponibilités alimentaires insuffisantes ; en fin de saison de reproduction, la température trop élevée et la mauvaise qualité des œufs sont sans doute en cause. Une fumure adéquate des étangs de grossissement des alevins et une alimentation correcte des géniteurs permettront peut-être de diminuer ces mortalités.

  3. EFFET DES VITAMINES B12, B9 ET B6 ET LEURS INTERACTIONS SUR LA FRAGILITE OSMOTIQUE DES ERYTHROCYTES HUMAINS

    Directory of Open Access Journals (Sweden)

    B HOUCHER

    2001-06-01

    Full Text Available L’effet des vitamines B12, B9 et B6 sur la fragilité osmotique des érythrocytes humains a été exploré in vitro. De fortes concentrations de vitamines B12 et B6 ont protégé les érythrocytes de l’hémolyse hypotonique, avec une protection maxima atteinte respectivement à 10 et 500 µg/ml. A concentrations plus faibles, cependant, ces vitamines ont favorisé grandement l’hémolyse hypotonique. Par contre, la vitamine B9 a montré uniquement un effet hémolytique de 4 à 200 µg/ml. Cet effet peut être expliqué par la nature acide de la molécule. L’effet nul sur la fragilité osmotique de deux vitamines antagonistes, peut probablement être expliqué par l’antagonisme partiel ou par la présence de ces deux vitamines simultanément: ces dernières se lient en quantités appréciables à la cellule intacte de même qu’à l’hémolysat et il y’ a compétition mutuelle entre ces vitamines et leur transport.

  4. Stabilization of spectra provided by a gamma-ray spectrometer. Application to the construction of a stabilizer; Stabilisation des spectres fournis par un spectrometre a rayons gamma. Application a la realisation d'un stabilisateur

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-06-15

    This research is concerned with the stabilization of spectra provided by a gamma-ray spectrometer. It is required to hold the calibration straight line of the spectrometer in a position which is fixed initially to better than 5x10{sup -5} channel. A prototype numerical stabilizer has been constructed : the SPECTROSTAB; it is made up of two independent control loops; one of these makes the spectrometer gain depend on the derivatives of a reference peak at high energies; the other makes the origin of the energy scale depend on the derivatives of a second reference peak at low energies A theoretical study of the behaviour of a control loop shows that a direct action stabilizer gives the most accurate stabilization; the loss in resolving power on the theoretical peaks of the spectra attains about 1 % with a scintillation detector, and 10 % with a semi-conductor detector. Various tests show that the expected results are obtained and that the displacement of the spectral peaks produced by the derivatives are hidden by errors in the calculation of the peak abscissae. (author) [French] Cette etude a pour objet la stabilisation des spectres fournis par un spectrometre a rayons gamma. On veut maintenir la droite d'etalonnage du spectrometre dans une position fixee initialement a mieux de 6.10{sup -5} canal pres. On realise un prototype de stabilisateur numerique, le SPECTROSTAB; il comprend deux boucles d'asservissement independantes; l'une d'elles asservit le gain du spectrometre aux derives d'un pic de reference aux hautes energies; l'autre asservit l'origine de l'echelle des energies aux derives d'un second pic de reference aux basses energies. Une etude theorique du comportement d'une boucle d'asservissement montre qu'un stabilisateur a action directe permet la stabilisation la plus precise; la perte en resolution sur les pics theoriques des spectres atteint environ 1 % avec un detecteur a scintillateur et 10 % avec un detecteur a semi-conducteur. Divers essais montrent

  5. Theoretical galactic cosmic ray electron spectrum obtained for sources of varying geometry; Spectre theorique des electrons du rayonnement cosmique dans la galaxie obtenu pour des sources a geometrie variable

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    Jokipii and Meyer have recently obtained an electron density energy spectrum of the cosmic rays, originating in the Galaxy, using integral solutions of the steady state transfer equations, by considering a circular cylindric galactic disc as source and approximating the resulting fourth order integral. In this report, we present general results, obtained by using an arbitrary circular cylindric source, without restricting ourselves to the galactic disc. The integrals are treated exactly. The conclusions of Jokipii and Meyer form special cases of these results. We also obtain an exponential energy variation which, at the moment, is not observed experimentally. The second part of this work deals with more complicated, but perhaps more realistic models of elliptic cylindric and ellipsoidal galactic disc sources. One may also note that a very large source concentrated in a very small region gives a spectrum not unlike that for a small source distributed throughout a large volume. Finally, it may be remarked that the model adopted is much less restrictive than the artificial conception of 'leakage time' followed by other workers. (author) [French] Jokipii et Meyer ont dernierement obtenu un spectre d'energie pour les electrons galactiques dans le rayonnement cosmique, en utilisant les solutions des equations de transfert, a l'etat stationnaire, ces dernieres etant sous forme d'integrales, en prenant une source completement diffusee dans le disque galactique, celui-ci etant hypothetiquement choisi comme circulaire et cylindrique et en faisant une approximation sur l'integrale du quatrieme degre. Dans ce rapport, nous presentons des resultats generaux obtenus en faisant appel a une source, diffusee dans un cylindre circulaire, arbitrairement choisi, c'est-a-dire sans nous restreindre au disque galactique comme source. Les integrales sont traitees d'une maniere exacte. Les conclusions de Jokipii et Meyer constituent des cas speciaux des resultats precedents. Nous obtenons

  6. UV imaging in pharmaceutical analysis

    DEFF Research Database (Denmark)

    Østergaard, Jesper

    2018-01-01

    UV imaging provides spatially and temporally resolved absorbance measurements, which are highly useful in pharmaceutical analysis. Commercial UV imaging instrumentation was originally developed as a detector for separation sciences, but the main use is in the area of in vitro dissolution...

  7. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: ''error-free'' bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases-the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation. (author)

  8. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

    Deep ultraviolet (DUV) photons interact strongly with a broad range of chemical and biological molecules; compact DUV light sources could enable a wide range of applications in chemi/bio-sensing, sterilization, agriculture, and industrial curing. The much shorter wavelength also results in useful characteristics related to optical diffraction (for lithography) and scattering (non-line-of-sight communication). The family of III-N (AlGaInN) compound semiconductors offers a tunable energy gap from infrared to DUV. While InGaN-based blue light emitters have been the primary focus for the obvious application of solid state lighting, there is a growing interest in the development of efficient UV and DUV light-emitting devices. In the past few years we have witnessed an increasing investment from both government and industry sectors to further the state of DUV light-emitting devices. The contributions in Semiconductor Science and Technology 's special issue on DUV devices provide an up-to-date snapshot covering many relevant topics in this field. Given the expected importance of bulk AlN substrate in DUV technology, we are pleased to include a review article by Hartmann et al on the growth of AlN bulk crystal by physical vapour transport. The issue of polarization field within the deep ultraviolet LEDs is examined in the article by Braut et al. Several commercial companies provide useful updates in their development of DUV emitters, including Nichia (Fujioka et al ), Nitride Semiconductors (Muramoto et al ) and Sensor Electronic Technology (Shatalov et al ). We believe these articles will provide an excellent overview of the state of technology. The growth of AlGaN heterostructures by molecular beam epitaxy, in contrast to the common organo-metallic vapour phase epitaxy, is discussed by Ivanov et al. Since hexagonal boron nitride (BN) has received much attention as both a UV and a two-dimensional electronic material, we believe it serves readers well to include the

  9. New measurements in plutonium L X ray emission spectrum using an electron probe micro-analyser; Nouvelles mesures dans le spectre d'emission L du plutonium au moyen d'un micro analyseur a sonde electronique

    Energy Technology Data Exchange (ETDEWEB)

    Bobin, J L; Despres, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    Further studies by means of an electron-probe micro-analyser, allowed report CEA-R--1798 authors to set up a larger plutonium X ray spectrum table. Measurements of plutonium L{sub II} and L{sub III} levels excitation potentials have also been achieved. Some remarks about apparatus performance data (such as spectrograph sensibility, resolving power and accuracy) will be found in the appendix. (authors) [French] Poursuivant les etudes exposees dans le rapport CEA-R--1798, les auteurs ont pu dresser un tableau plus etendu du spectre L du plutonium, au moyen du micro-analyseur a sonde electronique. Ils ont egalement effectue des mesures de potentiel d'excitation des niveaux L{sub II} et L{sub III} du plutonium. On trouvera en annexe quelques notes sur les constantes d'appareillage (sensibilite, pouvoir de resolution et precision des spectrographes). (auteurs)

  10. Inventaire des cavités souterraines abandonnées et cartographie des dangers qui leur sont liés

    Directory of Open Access Journals (Sweden)

    Claire ARNAL

    1994-12-01

    Full Text Available Un inventaire national des cavités souterraines abandonnées, des accidents de sol qui leur sont imputables et de leurs conséquences dommageables a été réalisé à l’échelle de 1/1 000 000 en 1993 et 1994 par le BRGM pour le ministère de l’Environnement (Direction de la Prévention des Pollutions et des Risques. Il a conduit à élaborer des documents cartographiques de synthèse et à définir des niveaux de dangers dont la localisation permettra de lancer des études plus détaillées en vue d’assurer la sécurité des personnes et des biens

  11. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  12. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: El ... Aug. 28, 2014 Keep an Eye on Ultraviolet (UV) Safety Eye medical doctors (ophthalmologists) caution us that ...

  13. UV-induced skin damage

    International Nuclear Information System (INIS)

    Ichihashi, M.; Ueda, M.; Budiyanto, A.; Bito, T.; Oka, M.; Fukunaga, M.; Tsuru, K.; Horikawa, T.

    2003-01-01

    Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed

  14. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

    The inactivation by ultraviolet (UV) light irradiation of mycoplasma cells of five human strains was monitored by investigating the colony-forming ability. The survival curves of five strains tested indicated that the cells of Mycoplasma buccale only are single and homogenously susceptible to UV light. The effect of the repair inhibitor, caffeine, on the colony-forming ability of UV-irradiated cells was investigated with M. buccale because of its homogeneous susceptibility to UV light. The colony formation of irradiated cells was markedly depressed by post-irradiation treatment with caffeine at concentration that had little or no effect on the colony formation of unirradiated cells. The colony-forming units (CFU) of UV-irradiated cells which were kept in broth without caffeine in the dark increased without a lag as the time in the dark increased. The colony-forming ability of the irradiated cells completely recovered after 3 hr in the dark. However, when irradiated cells were kept in the presence of caffeine, no increase in their CFU was observed. The mode of action of caffeine on UV-irradiated cells closely resembles that described for other organisms which possess dark reactivation systems for UV-induced damage in deoxyribonucleic acid. Thus, the results obtained provide evidence for the existence of a dark repair function in M. buccale. (author)

  15. Computer processing of {gamma} spectra. Application to the dosage of mixed natural or artificial radioelements; Traitement par ordinateur des spectres {gamma}. Application au dosage de melanges de radioelements naturels ou artificiels

    Energy Technology Data Exchange (ETDEWEB)

    Coulomb, R; Goldsztein, M; Schiltz, J C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    A program, written in Fortran II for IBM 7034 II, permitting resolution by means of least squares of a mixture of natural or artificial radioelements, is described. The spectra are processed in measurement batches, making up a homogeneous study, which comprise standards and samples. This highly versatile program may either ensure the processing of a great number of daily analyses, or be used pending development of radiochemical methods. The feeding of data has been simplified as much as possible. On the contrary, at the outlet, the numerical or graphical controls, error computations, and the printing of results in clear and legible form have been multiplied. In spite of this, the calculation times are exceedingly short. Several independent studies which include about sixty spectra may be processed in less than five minutes. (authors) [French] On decrit un programme, redige en Fortran H, pour IBM 7094 H, permettant la resolution par les moindres carres d'un melange de radioelements naturels ou artificiels. Les spectres sont traites par groupe de mesures, constituant une etude homogene, comprenant etalons et echantillons. Ce programme, extremement souple, peut, soit repondre a une production journaliere importante d'analyses, soit etre utilise en periode de mise au point de methodes radiochimiques. L'introduction des donnees a ete simplifiee au maximum. Au contraire, a la 'sortie', on a multiplie les controles numeriques ou graphiques, les calculs d'erreur, les impressions de resultats sous une forme aussi claire et lisible que possible. Malgre cela, les temps de calculs sont extremement brefs, plusieurs etudes independantes comportant une soixantaine de spectres peuvent etre traitees en moins de 5 minutes. (auteurs)

  16. Les biofilms bactériens : leur importance en santé animale et en santé publique

    Science.gov (United States)

    Tremblay, Yannick D.N.; Hathroubi, Skander; Jacques, Mario

    2014-01-01

    Résumé Les biofilms bactériens sont des amas structurés de cellules bactériennes enrobés d’une matrice polymérique et attachés à une surface. Le biofilm protège les bactéries et leur permet de survivre dans des conditions environnementales hostiles. Les bactéries du biofilm peuvent résister à la réponse immunitaire de l’hôte et sont beaucoup plus résistantes aux antibiotiques et aux désinfectants que les cellules bactériennes planctoniques. La capacité de former un biofilm est maintenant reconnue comme une caractéristique propre à plusieurs microorganismes. La présence de biofilms lors d’infections demande donc de nouvelles méthodes de prévention, de diagnostic et de traitement. De même, la présence de biofilms sur des surfaces retrouvées à la ferme, à l’abattoir ou à l’usine de transformation affectera l’efficacité du protocole de désinfection. De façon surprenante, la formation de biofilms chez les bactéries pathogènes des animaux et les bactéries zoonotiques est un sujet relativement peu étudié. Ce bref compte rendu a pour objectif de sensibiliser les intervenants en santé animale à l’importance des biofilms. PMID:24688172

  17. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  18. Regards critiques des jeunes Marocains sur leur place dans la vie politique nationale et les mobilités vers l’Europe

    Directory of Open Access Journals (Sweden)

    Zoubir Chattou

    2015-06-01

    Full Text Available L’objet de cet article est d’expliciter les aspirations politiques des jeunes au Maroc et leurs perceptions des mobilités transnationales. Rappelons que la thématique de la jeunesse a suscité un intérêt particulier ces dernières années au sein de ce Maroc en mouvement. En effet, le Pays connaît des changements profonds au niveau politique, économique, démographique et socioculturel qui ont incontestablement affecté les perceptions des jeunes selon la diversité de leurs profils. Ces changements touchent également les structures de pouvoir, les organisations de la société civile, les droits humains et l’évolution des rapports Nord/Sud. Il s’agit donc dans ce travail de saisir le regard critique des jeunes interviewés de l’ordre national et de ses articulations avec le niveau mondial. Ceci rend plus visible leur revendication d’une citoyenneté effective à la fois à l’échelle nationale et mondiale. Plusieurs focus groupes de jeunes (65 jeunes lycéens et du supérieur d’origines rurale et citadine ont été organisés dans le cadre de cette étude.

  19. UV/EB curable psa's

    International Nuclear Information System (INIS)

    Glotfelter, C.A.

    1995-01-01

    The author describe both water-based and 100% solids UV/EB curable PSA's (Pressure Sensitive Adhesives) and their properties. A new acrylate monomer, ethoxylated nonyl phenol acrylate, has great utility in the formulation of water-based PSA's

  20. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  1. Two-components UV-therapy

    International Nuclear Information System (INIS)

    Pullmann, H.; Steigleder, G.K.

    1980-01-01

    20 patients with generalized psoriasis were treated with an apparatus containing UV-A- and UV-B-fluorescence tubes to be switched separately. The therapy was started with an UV-A-dose of 12 J/cm 2 daily. After the first week of treatment UV-B in increasing doses was applicated additionally. Clearance was achieved in 80 percent. (orig.) [de

  2. Frequency Spectrum of Liquids and Cold Neutron Scattering; Spectre de frequences des liquides et diffusion de neutrons froids; Chastotnyj spektr zhidkostej i rasseyanie kholodnykh nejtronov; Espectro de frecuencias de los liquidos y dispersion de neutrones frios

    Energy Technology Data Exchange (ETDEWEB)

    Singwi, K S; Sjolander, A; Rahman, A [Argonne National Laboratory, Argonne, IL (United States)

    1963-01-15

    An important question which arises in connection with slow neutron scattering by liquids is: does there exist a frequency spectrum tor liquids analogous to that in solids? The answer to this question is given by showing that the width function {gamma}(t) of the Gaussian space-time self-correlation function G{sub s}(r,t) can be expressed, by using the frequency spectrum of the velocity auto-correlation function, in a form which is formally identical with that of a harmonic solid. Thus a knowledge of the frequency spectrum of the velocity auto-correlation function should enable one to calculate slow neutron scattering by liquids as has been emphasized by Egelstaff and co-workers. Using a stochastic model of a liquid, the frequency spectrum f({omega}) of the velocity auto-correlation function is calculated for water at 300{sup o}K and for liquid lead at 620{sup o}K. In the case of water a maximum in f({omega}) corresponding to {Dirac_h} 75{sup o}K is predicted. For lead the maximum also occurs at nearly the same {omega}-value. There also occurs a minimum in f({omega})in both cases. Larsson and Dahlborg have observed a maximum in f({omega}) at the above predicted {omega}-value. A recent observation in liquid lead of Cotter et al. probably confirms our prediction too. (author) [French] Dans le domaine de la diffusion des neutrons lents par des liquides une question importante se pose: existe-t-il un spectre de frequences pour les liquides analogue au spectre pour les solides? On peut repondre d cette quesnon en montrant que la fonction de largeur {gamma}(t) de la fonction gaussienne spatio-temporelle d'auto-correlation G{sub s}(r,t) peut etre exprimee, en employant le spectre de frequences de la fonction d'auto-correlation des vitesses, sous uune forme qui presente le membe aspect formel que celle d'un solide harmonique. par consequent, la connaissance du spectre de frequences de la fonction d'auto-correlation des vitesses devrait permettre de calculer la diffusion des

  3. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  4. UV-indeks og dets betydning

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Eriksen, Paul

    2010-01-01

    The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

  5. Des médailles et leurs revers. Des anciens d’Espagne devenus « héros des peuples de Yougoslavie »

    Directory of Open Access Journals (Sweden)

    Hervé Lemesle

    2011-11-01

    Full Text Available 64 des 1 900 Yougoslaves engagés en Espagne aux côtés des républicains ont obtenu le titre de « Héros des peuples de Yougoslavie ». Pourquoi eux ?Parmi les quelque 1 900 Yougoslaves engagés dans le camp républicain pendant la guerre d’Espagne (1936-1939, 64 ont obtenu le titre de « Héros des peuples de Yougoslavie », le plus prestigieux de la Yougoslavie titiste. Tous militants du Parti communiste à leur retour au pays après l’Espagne et l’internement dans les camps français, ils jouent un rôle de tout premier plan dans l’armée des partisans dirigée par Josip Broz Tito à partir de 1941. Après 1945, les 34 « Espagnols » morts pendant la Seconde Guerre mondiale sont auréolés de gloire et les 30 survivants, devenus des légendes vivantes, occupent des postes-clé dans l’armée, la diplomatie, le gouvernement et le Parti. Mais derrière le mythe, des zones d’ombre longtemps restées taboues existent. Grâce aux archives disponibles à Belgrade et à Moscou, on peut désormais retracer les itinéraires réels de ces militants, avec leurs faiblesses, leurs doutes, leurs désaccords.About the few Yugoslavs involved in the Spanish Civil War and granted the title “People’s Hero of Yugoslavia”.Among the few 1900 Yugoslavs involved in the Republican side during the Spanish Civil War (1936-1939, 64 were granted the title “People’s Hero of Yugoslavia”, the most prestigious of Tito’s Yugoslavia. All Communist Party militants on their return home after fighting in Spain and the French internment camps, they play a key role in the partisan army led by Josip Broz Tito in 1941. After 1945, the 34 “Spaniards” who died during World War II are crowned with glory and the 30 survivors, now living legends, occupy key positions in the military, diplomacy, government and the Party. But behind the myth, some aspects which remained taboo for long still exist. Thanks to the available archives in Belgrade and

  6. Quand le jugement médical met à l'épreuve le rapport des parents à leur enfant: le cas de l'autisme.

    OpenAIRE

    Borelle , Céline

    2010-01-01

    Cette communication s'appuie sur un travail de recherche portant sur les parcours de diagnostic et de prise en charge d'enfants pour lesquels sont évoqués les troubles envahissants du développement (TED) ou l'autisme à un moment donné de leur trajectoire. L'objectif de cette recherche est de saisir le parcours de ces enfants comme un processus non linéaire, marqué par l'implication de personnes ayant des positionnements différents par rapport à l'enfant (parents, proches, professionnels de la...

  7. Soutien aux enseignants dans leur pratique d'évaluation en mathématiques : effets sur les compétences des élèves

    NARCIS (Netherlands)

    Veldhuis, M.; Van den Heuvel-Panhuizen, M.; Zhao, X.

    2016-01-01

    Dans le cadre de deux études dans deux pays – les Pays-Bas et la Chine – nous avons étudié les effets sur l’apprentissage des élèves, d’une formation des enseignants en mathématiques sur leur pratique d’évaluation. L’échantillon de l’étude Néerlandaise était composé de 616 élèves et de 30

  8. Near UV Aerosol Group Report

    Science.gov (United States)

    Torres, Omar

    2013-01-01

    2012-13 Report of research on aerosol and cloud remote sensing using UV observations. The document was presented at the 2013 AEROCENTER Annual Meeting held at the GSFC Visitors Center, May 31, 2013. The Organizers of the meeting are posting the talks to the public Aerocentr website, after the meeting.

  9. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  10. Linear-logarithmic converter of a multi-channel selector-analyser type SA40 for automatic tracing; Convertisseur lineaire logarithmique pour le trace automatique de spectres d'un selecteur SA40

    Energy Technology Data Exchange (ETDEWEB)

    Desmaretz, M; Espanel, P; Ferlicci, R; Feyt, J

    1967-11-01

    The converter described in this note has been built to give the spectra stored in the memory of a type Sa40 selector in semi logarithmic coordinates. It must answer to several functions from numerical information appearing at the output of the selector - to command the address advance of the selector. - to decode numerical information and to transform it in analog tensions. - to operate the linear - logarithmic transformation for the register. - to send an start order to the table servo-motors. [French] L'appareil decrit dans la presente note a ete construit pour delivrer en coordonnees semi-logarithmiques les spectres stockes dans la memoire d'un selecteur type Sa40. Il doit remplir plusieurs fonctions a partir des informations numeriques apparaissant a la sortie parallele du selecteur - Commander l'avance adresse du selecteur. - decoder les informations numeriques et les transformer en tensions analogiques. - operer la transformation lineaire-logarithmique pour le registre. - envoyer un ordre de depart aux servo-moteurs de la table. (auteurs)

  11. Savoirs mondains, savoirs savants : les femmes et leurs cabinets de curiosités au siècle des Lumières

    Directory of Open Access Journals (Sweden)

    Adeline Gargam

    2010-01-01

    Full Text Available Dans la France des Lumières, la culture de la curiosité est un phénomène de mode mais surtout un jeu social et intellectuel. La présente étude entend retracer l’histoire d’une trentaine de cabinets féminins de curiosité tenus à cette époque. Des femmes fortunées de l’aristocratie et de la bourgeoisie parisienne et provinciale ont alors constitué sous l’emprise de leur libido sciendi des cabinets d’alchimie, de minéralogie, de physique‑chimie, d’histoire naturelle et d’anatomie naturelle et artificielle. Ces cabinets obéissent à une typologie particulière. Il en existe deux catégories : les cabinets d’amateurs, constitués pour la parade et le spectacle des visiteurs et fonctionnant comme de véritables écoles de plaisirs intellectuels et éducatifs ; les cabinets à finalité scientifique et didactique, formés par des savantes expérimentées qui se livrent dans leurs laboratoires à des recherches personnelles et expérimentales au nom des progrès de la science médicale et de l’instruction publique. La réflexion porte aussi sur le fonctionnement de ces cabinets privés de curiosité, particulièrement sur leur mode de constitution, leur décor intérieur ainsi que sur le contenu des collections qui nécessitaient certaines techniques d’organisation, d’acquisition et de conservation communes à celles de leurs homologues masculins.During the Enlightenment in France, curiosity culture constituted both a fashion and an intellectual and social game.  This article explores thirty cabinets of  curiosities run by women during this period. Wealthy women from the Parisiain and provincial aristocracy and middle classes organized cabinets in alchemy, mineralogy, physics and chemistry, natural history and biology studies. These cabinets can be divided into two distinct categories. The first represented amateur interests; they were developed for show and served as schools for intellectual and

  12. Changes in UV absorption of sunscreens after UV irradiation

    Science.gov (United States)

    Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

    2000-03-01

    In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

  13. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  14. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  15. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  16. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Sun lamps and tanning equipment emit ultraviolet (UV) rays. People who are exposed to UV rays over a long period of time are more likely to develop skin cancer. People with light skin are in more danger because their skin is more sensitive to UV rays.

  17. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  18. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  19. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  20. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

    Science.gov (United States)

    Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

    2011-02-01

    A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  2. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  3. UV lamp for photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Cardoso, M.J.B.; Landers, R.; Sundaram, V.S.

    1983-01-01

    An UV lamp and a differential pumping system which enables to couple the lamp to an ultra-high vacuum chamber (10 -9 torr) without using windows, are described. The differential between the pressure inside the discharge chamber and the one in de UHV region, which is of 10 8 -10 9 , is achieved with two pumping states separated by pyrex capillaries having an internal diameter of 0.6 mm. In the first stage, a mechanical pump (10 -3 torr) is used; in the second stage, a diffusor pump with a cryogenic trap (N 2 liq - 10 -7 torr) is employed. The lamp produces, when used with high purity He, narrow lines almost clear at 21.2 eV and 40.8 eV, depending on the discharge chamber pressure, thus eliminating the need of a monochromator. As a high voltage source (3 KV), a commercial unit with a good current control was used, ensuring UV beam stability - an essential characteristic for this lamp if it is employed for photoelectron excitation of crystalline samples. (C.L.B.) [pt

  4. Efficiency of ocular UV protection by clear lenses.

    Science.gov (United States)

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-04-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

  5. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  6. [Light protection: principles of UV protection].

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

    UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

  7. UV-Induced Cell Death in Plants

    Science.gov (United States)

    Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-01

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280–320 nm) and UV-A (320–390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD). PMID:23344059

  8. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  9. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  10. The UV Survey Mission Concept, CETUS

    Science.gov (United States)

    Heap, Sara; and the CETUS Team

    2018-01-01

    In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

  11. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

    Several technologies are currently being developed, leading to substantial improvements in the performance of UV detectors or significant reductions in power or weight. Four technologies discussed are (1) thin-film coatings to enhance the UV sensitivity of CCD's, (2) highly innovative magnet assemblies that dramatically reduce weight and result in virtually no external flux, (3) new techniques for curving microchannel plates (MCP's) so that single plates can be used to prevent ion feedback and present highly localized charge clouds to an anode structure, and (4) high-performance alternatives to glass-based MCP's. In item (2), for example, very robust magnets are made out of rare earth materials such as samarium cobalt, and cladding magnets are employed to prevent flux from escaping from the detector into the external environment. These new ultralight magnet assemblies are able to create strong, exceptionally uniform magnetic fields for image intensification and focusing of photoelectrons. The principle advantage of such detectors is the quantum efficiencies of 70-80 percent obtained throughout ultraviolet wavelengths (900-2000 A), the highest of any device. Despite the improvements achieved under item (3), high-performance alternatives to conventional glass-based MCP's potentially offer three distinct new advantages that include (1) a 30-100-fold improvement in dynamic range resulting in correspondingly higher signal-to-noise ratios, (2) the use of pure dielectric and semiconductor materials that will not outgas contaminants that eventually destroy photocathodes, and (3) channels that have constant spacing providing long-ranged order since the plates are made using photolithography techniques from the semiconductor industry. The manufacturers of these advanced-technology MCP's, however, are a couple of years away from actually producing a functioning image intensifier. In contrast to the use of CCD's for optical, ground based observations, there is no single

  12. UV-extending Ghost Inflation

    CERN Document Server

    Ivanov, Mikhail M

    2014-01-01

    We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.

  13. Expression of UV-irradiated adenovirus in normal and UV-sensitive Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1985-01-01

    The chinese hamster ovary (CHO) cell mutants UV-20, UV-24, and UV-41 are abnormally sensitive to UV and harbour various defects lin their ability to repair cellular DNA. This study has examined the expression of UV-irradiated AD2 in these cells. HCR of UV-irradiated Ad2, as measured by viral structural antigen (Vag) formation or progeny production, was found to be similar for the normal and the UV-sensitive CHO strains. UV-irradiation of Ad2 (1200 J/m/sup 2/) resulted in a delay of Vag expression of 18 hours in normal human fibroblasts, which is thought to reflect the time required for removal of UV-induced lesions from the DNA before viral DNA synthesis can proceed. However, a similar UV-irradiation of Ad2 did not result in a delay of Vag expression for infection of CHO cells, suggesting that UV-induced lesions in Ad2 DNA do not inhibit its replication in CHO cells. These results indicate a fundamental difference in the processing of UV-irradiated AD2-DNA in CHO as compared to human cells

  14. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K; Leszczynski, K; Visuri, R; Ylianttila, L [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  15. UV dichroic coatings on metallic reflectors

    International Nuclear Information System (INIS)

    Raghunath, C; Babu, N J; Chandran, K M

    2008-01-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail

  16. UV dichroic coatings on metallic reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Raghunath, C; Babu, N J; Chandran, K M [Hind High Vacuum Co. Pvt. Ltd. No.17, Phase 1, Peenya Industrial Area, Bangalore 560058 (India)

    2008-05-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail.

  17. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in

  18. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  19. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  20. Direct UV-writing of waveguides

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz

    2003-01-01

    induced refractive index change of more than 10-2 have been obtained. New insight, with respect to understanding the UV induced index change obtained by direct UV writing, has been provided, through experiments conducted with such high-pressure loaded germanosilica samples. This include measurements...

  1. Effect of UV laser irradiation on tissue

    International Nuclear Information System (INIS)

    Nakayama, Takeyoshi; Kubo, Uichi

    1992-01-01

    Laser-tissue interactions have been investigated through Electron Probe Micro Analysis (EPMA), UV-visible optical absorption and Fourier Transform Infrared Spectroscopy (FTIR). Three excimer lasers, ArF, KrF and XeCl, were used to irradiate tissue; cow thighbone and gelatin thin film. Features of UV laser irradiation are described. (author)

  2. uv photobiology: DNA damage and repair

    International Nuclear Information System (INIS)

    Sutherland, B.M.

    1978-01-01

    The following topics are discussed: targets that determine the fate of the cell when uv light interacts with a cell; comparison of action spectrum for a given biological effect with the absorption spectrum of different biological macromolecules; biological effects of damage to DNA; measurement of mutations; chemical damage to DNA; photoreactivation; role of pyrimidine dimers in induction of skin cancer by uv

  3. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  4. UV Reconstruction Algorithm And Diurnal Cycle Variability

    Science.gov (United States)

    Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

    2009-03-01

    UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

  5. The n,{gamma} discrimination in recoil-proton proportional counters. Application to the measurement of fast neutron spectra; Discrimination n,{gamma} dans les compteurs proportionnels a protons de recul. Application a la mesure des spectres de neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    A description is given of a spectrometry chain working in the energy range of a few keV to 1 MeV, and designed for measurement of fast neutron spectra. It consists of detectors, recoil proton proportional counters built especially for this work by R. COMTE (DEG/SER) and which make it possible to cover the energy range and also associated electronic equipment. A brief description is first given of the physical processes involved: (n,p) collisions in the gas, influence of {gamma} radiation; the method of discrimination is then presented. It is based on the difference in the rise-times of the pulses. In the experiments described here the use of a bi-parametric system made it possible to employ the most simple discrimination device, based on the fact that the high frequency gamma pulse components are, at a given energy, weaker than those of the neutron pulses. Results are given of measurements carried out on the Van der Graaff (mono-energetic neutrons for testing the linearity of the chain and the resolving power of the counters), and of those made in a sub-critical system Hug at Cadarache. (author) [French] On decrit une chaine de spectrometrie travaillant dans le domaine d'energie de quelques keV a 1 MeV destinee a la mesure des spectres de neutrons rapides. Elle comprend les detecteurs, compteurs proportionnels a protons de recul, realises specialement pour cette etude par M. R. COMTE (DEG/SER), permettant de couvrir la gamme d'energie et l'electronique associee. Apres un rappel des processus physiques mis en jeu: chocs (n,p) dans les gaz, influence des rayonnements {gamma}, on expose la methode de discrimination utilisee. Celle-ci est basee sur la difference des temps de montee des impulsions. Au cours des experiences rapportees ici, la mise en oeuvre d'un ensemble bi-parametrique a permis d'utiliser le dispositif de discrimination le plus simple, base sur la remarque que les composantes a haute frequence des impulsions {gamma} sont, a energie egale, plus faibles

  6. The n,{gamma} discrimination in recoil-proton proportional counters. Application to the measurement of fast neutron spectra; Discrimination n,{gamma} dans les compteurs proportionnels a protons de recul. Application a la mesure des spectres de neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    A description is given of a spectrometry chain working in the energy range of a few keV to 1 MeV, and designed for measurement of fast neutron spectra. It consists of detectors, recoil proton proportional counters built especially for this work by R. COMTE (DEG/SER) and which make it possible to cover the energy range and also associated electronic equipment. A brief description is first given of the physical processes involved: (n,p) collisions in the gas, influence of {gamma} radiation; the method of discrimination is then presented. It is based on the difference in the rise-times of the pulses. In the experiments described here the use of a bi-parametric system made it possible to employ the most simple discrimination device, based on the fact that the high frequency gamma pulse components are, at a given energy, weaker than those of the neutron pulses. Results are given of measurements carried out on the Van der Graaff (mono-energetic neutrons for testing the linearity of the chain and the resolving power of the counters), and of those made in a sub-critical system Hug at Cadarache. (author) [French] On decrit une chaine de spectrometrie travaillant dans le domaine d'energie de quelques keV a 1 MeV destinee a la mesure des spectres de neutrons rapides. Elle comprend les detecteurs, compteurs proportionnels a protons de recul, realises specialement pour cette etude par M. R. COMTE (DEG/SER), permettant de couvrir la gamme d'energie et l'electronique associee. Apres un rappel des processus physiques mis en jeu: chocs (n,p) dans les gaz, influence des rayonnements {gamma}, on expose la methode de discrimination utilisee. Celle-ci est basee sur la difference des temps de montee des impulsions. Au cours des experiences rapportees ici, la mise en oeuvre d'un ensemble bi-parametrique a permis d'utiliser le dispositif de discrimination le plus simple, base sur la remarque que les composantes a haute frequence des impulsions {gamma} sont, a

  7. UV-straling in de kas: mogelijkheden en grenzen

    NARCIS (Netherlands)

    Hoffmann, S.

    2000-01-01

    Effect van UV-straling op kleuring van Coleus Blumei 'Wizzard Velvit Red'. Gegevens in bijgaande tabellen: 1) Indeling optische straling; 2) Transmisse voor UV-straling van verschillende dekmaterialen (folie UV, glas UV, glas normaal, folie normaal, folie UV-blok

  8. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

    UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.

  9. Elimination of slightly radioactive liquid effluent by dilution. Its consequences (1960); Elimination par dilution d'effluents liquides faiblement radioactifs. Leurs consequences (1960)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    Nuclear centres often have to solve problems raised by the elimination of large volumes of slightly radioactive liquid effluent. As things stand at present, the method usually adopted consists in expelling this effluent into the main water system in order to dilute it to a maximum, and thus to lower its radioactive isotope concentration to below the norms imposed by the Public Health Service. This technique requires systematic checking of the water system and its dependences, and demands a thorough knowledge of adsorption and fixation processes. (author) [French] Les centres nucleaires ont frequemment a resoudre des problemes poses par l'elimination de volumes importants d'effluents liquides faiblement radioactifs. Dans l'etat actuel des choses, la solution la plus utilisee consiste a rejeter ces effluents dans le reseau hydrographique de maniere a les diluer au maximum et abaisser ainsi leurs teneurs en isotopes radioactifs au-dessous des normes imposees par la Sante Publique. Cette technique necessite un controle systematique du reseau et de ses dependances et demande une connaissance approfondie des processus d'adsorption et de fixation. (auteur)

  10. Specific heat measurements on metals up to their melting point; Mesure de la chaleur specifique des metaux jusqu'a leur temperature de fusion

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-07-15

    We have built an apparatus to measure the specific heat of metal up to the melting point. The method is the pulse-heating method, where the specimen is heated very rapidly (1/10 s) from room temperature to the melting point by a very intense d.c. current (1000 A). The simultaneous measurements of intensity, voltage and temperature in the specimen allows a calculation of the specific heat. We have obtained good results for niobium, tungsten, tantalum and uranium. The accuracy is around 3 to 5 per cent and allows a measurement of the heat of formation of vacancies near the melting temperature. (author) [French] Nous avons construit un appareil permettant la mesure de la chaleur specifique des metaux jusqu'a leur temperature de fusion. La methode utilisee est la methode dite de chauffage instantane, L'echantillon est echauffe tres rapidement (1/10 s) de la temperature ambiante a la temperature de fusion par le passage d'un courant tres intense ({approx} 1000 A). L'enregistrement simultane de l'intensite du courant, de la difference de potentiel aux bornes de l'echantillon et de la temperature, permet de calculer la chaleur specifique. Nous avons obtenu de bons resultats pour le niobium, le tungstene tantale et l'uranium. La precision de la methode est de l'ordre de 3 a 5 pour cent et permet une mesure de la chaleur de formation des lacunes au voisinage de la fusion. (auteur)

  11. Multi-channel recording of a pulse spectrum on the screen of a Williams tube used with a ferrite memory analyser; Enregistrement du spectre d'impulsion sur l'ecran d'un tube de Williams au moyen d'un analyseur multicanal a memoire en ferrite; Zapis' spektra impul'sov na ehkrane ehlektronno-luchevoj trubki mnogokanal'nogo analizatora s ferritovoj pamyat'yu; Registro multicanal del espectro de los impulsos en la pantalla del tubo electronico, en un analizador con memoria de ferrita

    Energy Technology Data Exchange (ETDEWEB)

    Rumler, Shtirad [Institut Yadernogo Issledovannya Chekhoslovatskoj Akldemii Nauk, Rzhezh Chekhoslovatskaya Sotsialisticheskaya Respublika (Czech Republic)

    1962-04-15

    mentionne. Cet enregistrement n'est pas assez precis, notamment lorsqu'on analyse des intermittentes caracterisees par une basse frequence de repetition et une faible moyenne du nombre des impulsions. La raison en est que le dechiffrage de l'information fournie s'effectue dans le canal a partir des circuits additionneurs et des circuits , l'enregistrement se passant directement sur l'ecran. L'insuffisance de l'enregistrement direct s'explique par la moyenne faible du nombre des impulsions et par leur distribution statistique. La methode proposee se revele dans le cas considere comme plus satisfaisante; en effet, la qualite de l'enregistrement ne depend ni de la forme du spectre ni de la vitesse de comptage des impulsions. Elle est utilisee dans le selecteur a 256 canaux dont la memoire en ferrite presente un temps mort de 15 microsecondes. Le cycle de la representation oscillographique alterne periodiquement avec celui de l'analyse du spectre a mesurer, la frequence de base etant de 50 Hz. Le temps necessaire a l'enregistrement oscillographique est d'environ 4 millisecondes soit 20% de la duree totale du cycle d'utilisation du selecteur dans les selecteurs ayant un nombre de canaux plus petit et une memoire en ferrite a temps mort plus court; la duree de l'enregistrement oscillographique ne represente qu'un faible pourcentage de la duree du cycle d'utilisation. (author) [Spanish] Se describe un diagrama de conjunto aplicable al establecimiento de programas operativos que permiten el registro multicanal de un espectro creciente de impulsos analizados en la pantalla del tubo electronico, en combinacion con una memoria estatica de ferrita. Los dipositivos comunes de registro directo en el tubo electronico, en algunos casos, resultan imperfectos en un analizador del tipo indicado. Se comprueba que el registro no es suficientemente claro, especialmente cuando se trata de analizar de impulsos momentaneos con baja frecuencia de repeticion y cuyo

  12. Plant responses to UV-B irradiation are modified by UV-A irradiation

    International Nuclear Information System (INIS)

    Middleton, E.M.; Teramura, A.H.

    1993-01-01

    The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

  13. Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

    Science.gov (United States)

    Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

    2018-03-01

    Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

  14. Radioactive decontamination through UV laser

    International Nuclear Information System (INIS)

    Delaporte, Ph.; Gastaud, M.; Sentis, M.; Uteza, O.; Marine, W.; Thouvenot, P.; Alcaraz, J.L.; Le Samedy, J.M.; Blin, D.

    2003-01-01

    A device allowing the radioactive decontamination of metal surfaces through the use of a pulsed UV laser has been designed and tested. This device is composed of a 1 kW excimer laser linked to a bundle of optic fibers and of a system to recover particles and can operate in active zones. Metal surfaces have the peculiarities to trap radio-elements in a superficial layer of oxide that can be eaten away by laser radiation. Different contaminated metals (stainless steels, INCONEL and aluminium) issued from the nuclear industry have been used for the testing. The most important contaminants were 60 Co, 137 Cs, 154-155 Eu and 125 Sb. The ratio of decontamination was generally of 10 and the volume of secondary wastes generating during the process was very low compared with other decontamination techniques. A decontamination speed of 1 m 2 /h has been reached for aluminium. The state of the surface is an important parameter because radio-elements trapped in micro-cracks are very difficult to remove. (A.C.)

  15. Méthode rapide de caractérisation des roches mètres, de leur potentiel pétrolier et de leur degré d'évolution Rapid Method for Source Rocks Characrerysation and for Determination of Petroleum Potential and Degree of Evolution

    Directory of Open Access Journals (Sweden)

    Espitalié J.

    2006-11-01

    Full Text Available Les études fondamentales réalisées sur les kérogènes à l'aide de diverses méthodes physico-chimiques d'analyse ont permis de mettre au point une méthode et un appareillage adaptés à l'exploration pétrolière. On expose dans cet article la mise au point de cette méthode et on montre, à l'aide des paramètres qu'elle permet d'obtenir, ses applications dans le domaine de l'exploration pétrolière - reconnaissance des différents types de roche mère et de leur potentiel pétrolier; - caractérisation de leur degré d'évolution (zone à huile - zone à gaz. On montre aussi que cette méthode convient particulièrement bien à l'estimation du rendement en huile des roches bitumineuses et à l'étude de la qualité et du rang des charbons. Fundamental research on kerogens by different physico-chemical analysis methods have led to the development of a method and equipment suited for petroleum exploration. This article describes the development of this method and, by means of the parameters it determines, shows how it con be applied in the field of petroleum exploration - exploring different types of source rock and their petroleum potential ; - characterizing their degree of evolution (ail zone/gas zone. This method is also shown ta be particularly suited for estimating the oil yield of cil shales and investigating the quality and classification of cool.

  16. Application of UV Imaging in Formulation Development

    DEFF Research Database (Denmark)

    Sun, Yu; Østergaard, Jesper

    2017-01-01

    defining formulation behavior after exposure to the aqueous environments and pharmaceutical performance is critical in pharmaceutical development, manufacturing and quality control of drugs. UV imaging has been explored as a tool for qualitative and quantitative characterization of drug dissolution...... related to the structural properties of the drug substance or formulation can be monitored. UV imaging is a non-intrusive and simple-to-operate analytical technique which holds potential for providing a mechanistic foundation for formulation development. This review aims to cover applications of UV...

  17. Global Solar UV Index (invited paper)

    International Nuclear Information System (INIS)

    Repacholi, M.H.

    2000-01-01

    Excessive solar ultraviolet (UV) radiation exposure produces a significant burden of disease to the skin, eyes and immune system. Effective programmes for the reduction of UV exposure are needed to reduce this disease burden and the associated health care costs. The UV index is seen as an effective tool for communicating important protection information to the public through its use in media news and weather information. The index is described and it is suggested that universally common messages should be associated with its ranges. (author)

  18. RPC industries - UV and EB equipment manufacturers

    International Nuclear Information System (INIS)

    Rodrigues, A.M.

    1987-01-01

    RPC Industries has been manufacturing electron beam and ultraviolet equipment for the industrial processing of materials for more than 15 years. RPC maintains its headquarters and electron processor manufacturing plant in Hayward, California. UV equipment is made in the company's plant near Chicago. Sales offices are maintained in New York, Illinois, and California in the USA, and in Germany, Japan, Australia, Italy, Israel, and Sweden. Complete testing and pilot facilities are available in Hayward (EB) and near Chicago (UV). Described below are the basic system components, applications and advantages of RPC's UV and EB systems. (orig.)

  19. Transformation of UV-hypersensitive Chinese hamster ovary cell mutants with UV-irradiated plasmids

    International Nuclear Information System (INIS)

    Nairn, R.S.; Humphrey, R.M.; Adair, G.M.

    1988-01-01

    Transfection of UV-hypersensitive, DNA repair-deficient Chinese hamster ovary (CHO) cell lines and parental, repair-proficient CHO cells with UV-irradiated pHaprt-1 or pSV2gpt plasmids resulted in different responses by recipient cell lines to UV damage in transfected DNA. Unlike results reported for human cells, UV irradiation of transfecting DNA did not stimulate genetic transformation of CHO recipient cells. In repair-deficient CHO cells, proportionally fewer transformants were produced with increasing UV damage than in repair-proficient cells in transfections with UV-irradiated hamster adenine phosphoribosyltransferase (APRT) gene contained in plasmid pHaprt-1. Transfection of CHO cells with UV-irradiated pSV2gpt resulted in neither decline in transformation frequencies in repair-deficient cell lines relative to repair-proficient cells nor stimulation of genetic transformation by UV damage in the plasmid. Blot hybridization analysis of DNA samples isolated from transformed cells showed no dramatic changes in copy number or arrangement of transfected plasmid DNA with increasing UV dose. The authors conclude responses of recipient cells to UV-damaged transfecting plasmids depend on type of recipient cell and characteristics of the genetic sequence used for transfection. (author)

  20. SSC spectre hovers over neutron project

    CERN Multimedia

    MacIlwain, C

    1999-01-01

    The 1.4 billion dollar project to build the world's most powerful neutron source at the Oak Ridge National laboratory, has fallen between 3 and 6 months behind schedule during its first year of construction. It now faces major difficulties in obtaini ng funding for next year (1 page).

  1. The Spectre of Race in American Medicine

    Science.gov (United States)

    Fofana, Mariam O.

    2014-01-01

    Controversies and debates surrounding race have long been a fixture in American medicine. In the past, the biological concept of race—the idea that race is biologically determined and meaningful—has served to justify the institution of slavery and the conduct of unethical research trials. Although these days may seem far behind, contemporary debates over the race-specific approval of drugs and the significance of genetic differences are evidence that race still yields tremendous influence on medical research and clinical practice. In many ways, the use of race in medicine today reflects the internalization of racial hierarchies borne out of the history of slavery and state-mandated segregation, and there is still much uncertainty over its benefits and harms. Although using race in research can help elucidate disparities, the reflexive use of race as a variable runs the risk of reifying the biological concept of race and blinding researchers to important underlying factors such as socioeconomic status. Similarly, in clinical practice, the use of race in assessing a patient’s risk of certain conditions (e.g., sickle cell) turns harmful when the heuristic becomes a rule. Through selected historical and contemporary examples, I aim to show how the biological concept of race that gave rise to past abuses remains alive and harmful and propose changes in medical education as a potential solution. By learning from the past, today’s physicians will be better armed to discern—and correct—the ways in which contemporary medicine perpetuates historical injustices. PMID:23988563

  2. The spectre of race in American medicine.

    Science.gov (United States)

    Fofana, Mariam O

    2013-12-01

    Controversies and debates surrounding race have long been a fixture in American medicine. In the past, the biological concept of race-the idea that race is biologically determined and meaningful-has served to justify the institution of slavery and the conduct of unethical research trials. Although these days may seem far behind, contemporary debates over the race-specific approval of drugs and the significance of genetic differences are evidence that race still yields tremendous influence on medical research and clinical practice. In many ways, the use of race in medicine today reflects the internalisation of racial hierarchies borne out of the history of slavery and state-mandated segregation, and there is still much uncertainty over its benefits and harms. Although using race in research can help elucidate disparities, the reflexive use of race as a variable runs the risk of reifying the biological concept of race and blinding researchers to important underlying factors such as socioeconomic status. Similarly, in clinical practice, the use of race in assessing a patient's risk of certain conditions (eg, sickle cell) turns harmful when the heuristic becomes a rule. Through selected historical and contemporary examples, I aim to show how the biological concept of race that gave rise to past abuses remains alive and harmful, and propose changes in medical education as a potential solution. By learning from the past, today's physicians will be better armed to discern-and correct-the ways in which contemporary medicine perpetuates historical injustices.

  3. The Spectre of Race in American Medicine

    OpenAIRE

    Fofana, Mariam O.

    2013-01-01

    Controversies and debates surrounding race have long been a fixture in American medicine. In the past, the biological concept of race—the idea that race is biologically determined and meaningful—has served to justify the institution of slavery and the conduct of unethical research trials. Although these days may seem far behind, contemporary debates over the race-specific approval of drugs and the significance of genetic differences are evidence that race still yields tremendous influence on ...

  4. Postfeminist Spectres: What Is Haunting Television Heroines?

    OpenAIRE

    Strehlau, Nelly

    2017-01-01

    Postfeminism is frequently analyzed and conceptualized as a time or sensibility haunted by the ghost of feminism that it wants to (purports to) relegate to the past. It is also a crucial concept in understanding the ways of portraying and constructing female characters prevalent in the American media. The article considers the hauntings (literal but predominantly fgurative) experienced by selected prominent women protagonists of postfeminist American mid-brow television series of the late 199...

  5. Une formation mixte (synchrone et asynchrone offerte en ligne pour le développement des compétences des enseignants dans leur milieu de travail : étude de cas

    Directory of Open Access Journals (Sweden)

    Louise Sauvé

    2008-01-01

    Full Text Available Apprendre tout au long de la vie amène de plus en plus les adultes, confrontés au fait de devoir concilier emploi, travail et études, à rechercher des solutions de formation à la carte selon des horaires fragmentés, près de leur lieu de travail ou de leur milieu de vie. Les technologies Web s’avèrent des outils par excellence pour soutenir ces formations puisqu’elles offrent flexibilité, accessibilité, communication et interaction tout en permettant une variété d’approches éducatives. Cet article présente le contexte et les résultats d’une étude de cas auprès de formateurs en milieu de travail ainsi que le programme de formation personnalisé de formateurs en ligne, Form@tion.

  6. New technology and application in UV curing

    International Nuclear Information System (INIS)

    Loutz, J.M.

    1999-01-01

    Overview of radcure technology was presented. Its included this following subjects, radiation curable powder coatings, UV curable water based polyurethanes, photo-initiators, fire retardancy, aqueous systems, cationic, ceramic and optical grade material

  7. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

    Due, Eva; Rossen, Kristian; Sorensen, Lars Tue

    2007-01-01

    The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV...... postoperatively, UV-irradiated cicatrices healing by second intention: (i) were significantly pointed out as the most disfiguring; (ii) obtained significantly higher scores of colour, infiltration and cicatrix area; and (iii) showed significantly higher increase in skin-reflectance measurements of skin......-pigmentation vs. non-irradiated cicatrices. No histological, immunohistochemical or biochemical differences were found. In conclusion, postoperative UV exposure aggravates the clinical appearance of cicatrices in humans....

  8. UV curable palm oil based ink

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Mohd Hilmi Mahmood; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil urethane acrylate (POBUA) as a prepolymer in the UV ink system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  9. UV curable palm oil based inks

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Hilmi Mahmood

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil based urethane acrylate (POBUA) as a prepolymer in the UV inks system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  10. Accelerated Solar-UV Test Chamber

    Science.gov (United States)

    Gupta, A.; Laue, E. G.

    1984-01-01

    Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

  11. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

    1994-12-31

    Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

  12. Road Signs for UV-Completion

    CERN Document Server

    Dvali, Gia; Gomez, Cesar

    2012-01-01

    We confront the concepts of Wilsonian UV-completion versus self-completion by Classicalization in theories with derivatively-coupled scalars. We observe that the information about the UV-completion road is encoded in the sign of the derivative terms. We note that the sign of the derivative couplings for which there is no consistent Wilsonian UV-completion is the one that allows for consistent classicalons. This is an indication that for such a sign the vertex must be treated as fundamental and the theory self-protects against potential inconsistencies, such as superluminality, via self-completion by classicalization. Applying this reasoning to the UV-completion of the Standard Model, we see that the information about the Higgs versus classicalization is encoded in the sign of the scattering amplitude of longitudinal W-bosons. Negative sign excludes Higgs or any other weakly-coupled Wilsonian physics.

  13. Mean Annual UV-B Irradiance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ultraviolet-B (UV-B) radiation is the most energetic part of sunlight reaching the Earth's surface (wavelength region is 280 to 315 nm), and it has been shown to...

  14. UV Impacts Avoided by the Montreal Protocol

    Science.gov (United States)

    Newman, Paul; McKenzie, Richard

    2010-01-01

    Temporal and geographical variabilities in the future "World Expected" UV environment are compared with the "World Avoided", which would have occurred without the Montreal Protocol on protection of the ozone layer and its subsequent amendments and adjustments. Based on calculations of clear-sky UV irradiances, the effects of the Montreal Protocol have been hugely beneficial to avoid the health risks, such as skin cancer, which are associated with high UV, while there is only a small increase in health risks, such as vitamin D deficiency, that are associated with low UV. However, interactions with climate change may lead to changes in cloud and albedo, and possibly behavioural changes which could also be important.

  15. Progress in deep-UV photoresists

    Indian Academy of Sciences (India)

    Unknown

    This paper reviews the recent development and challenges of deep-UV photoresists and their ... small amount of acid, when exposed to light by photo- chemical ... anomalous insoluble skin and linewidth shift when the. PEB was delayed.

  16. Remote UV Fluorescence Lifetime Spectrometer, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  17. UV sensitivity of various solid state detectors

    International Nuclear Information System (INIS)

    Knezevic, Zeljka; Ranogajec-Komor, Maria; Miljanic, Saveta

    2008-01-01

    Full text: The light sensitivity is an important characteristic of solid state passive dosimeters used in individual, clinical and environmental dosimetry. Light sensitivity stands for the response directly induced by visible or UV light in a fully annealed material. For the above mentioned applications a negligible light sensitivity is an advantage. However, high light sensitivity and linear response allows the use of detectors as UV dosimeters. For this purpose various TL detectors and the glass element of the RPL dosemeter type SC-1 were systematically investigated after exposure to UV light (254 and 366 nm) as a function of time. The following solid state detectors were investigated relative to TLD-100: Li 2 B 4 O 7 :Cu,Ag,P LiF:Mg,Cu,P, LiF:Mg,Cu,Si, Al 2 O 3 :C and the glass element of RPL dosimeter. UV irradiations were performed with Camag UV lamp at 254 nm and at 366 nm. The illumination times were 5, 10 and 20 minutes. Day light illumination was also carried out at room temperature over time period of several hours up to 2 weeks. The UV light response of each detector was compared to the response obtained after irradiation with 137 Cs. Al 2 O 3 :C, showed high light sensitivity; after 10 minutes illumination with 254 nm UV light the response was equivalent to 130 mGy 137 Cs gamma irradiation. The 254 nm UV response of LiF:Mg,Cu,P (GR-200 A), as well as TLD-700H and Li 2 B 4 O 7 :Cu,Ag,P were proportional to the time of illumination. The responses after 10 min UV illumination were equivalent to 0.001 mGy, 0.01 mGy and 0.1 mGy 137 Cs gamma irradiation, respectively. The complete SC-1 RPL dosimeter is insensitive to light because the glass element is encapsulated in light protected holder throughout the automatic evaluation process following the annealing (irradiation, preheat, readout). The responses of the previously annealed glass element after 20 min illumination with 254 nm and 366 nm UV light were equivalent to 45μSv and 3 μSv of 137 Cs gamma

  18. Dynamic Optimization of UV Flash Processes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

    2017-01-01

    UV ash processes, also referred to as isoenergetic-isochoric ash processes, occur for dynamic simulation and optimization of vapor-liquid equilibrium processes. Dynamic optimization and nonlinear model predictive control of distillation columns, certain two-phase ow problems, as well as oil reser...... that the optimization solver, the compiler, and high-performance linear algebra software are all important for e_cient dynamic optimization of UV ash processes....

  19. Bactericidal effectiveness of modulated UV light

    International Nuclear Information System (INIS)

    Bank, H.L.; John, J.; Schmehl, M.K.; Dratch, R.J.

    1990-01-01

    Studies were designed to evaluate the effectiveness of pulsed modulated UV light waveforms for killing bacteria. Exposure of five strains of bacteria to the modulated information encoded in the light decreased the colony population from a confluent lawn to less than 20 colonies. However, approximately 2,000 colonies survived treatment with the same intensity and time of exposure to UV light lacking the modulated information

  20. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E; Thomalla, E; Koepke, P [Munich Univ. (Germany). Meteorological Inst.

    1996-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  1. UV spectra, bombs, and the solar atmosphere

    OpenAIRE

    Judge, Philip G.

    2015-01-01

    A recent analysis of UV data from the Interface Region Imaging Spectrograph {\\em IRIS} reports plasma "bombs" with temperatures near \\hot{} within the solar photosphere. This is a curious result, firstly because most bomb plasma pressures $p$ (the largest reported case exceeds $10^3$ dyn~cm$^{-2}$) fall well below photospheric pressures ($> 7\\times10^3$), and secondly, UV radiation cannot easily escape from the photosphere. In the present paper the {\\em IRIS} data is independently analyzed. I...

  2. Chronic effects of UV on human skin

    International Nuclear Information System (INIS)

    Cesarini, J.P.

    1996-01-01

    Chronic exposures and acute accidents of the skin to UV has been recognized as an important risk for skin cancers in human. Attempts have been made with mathematical models to correlate the ambient UV dose and occupational irradiations with the risk of skin cancers. Development of accurate global measurements of solar irradiance and personal dosimetry is expected in the future in order to reduce the exposure of the general population, to precise the measures to be taken for indoor and outdoor workers. (author)

  3. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  4. UV written 1x8 optical splitters

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed.......In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed....

  5. Accurate modeling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  6. Accurate modelling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  7. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E.; Thomalla, E.; Koepke, P. [Munich Univ. (Germany). Meteorological Inst.

    1995-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  8. Les représentations des enseignants quant à leurs profils de compétences relatives à l’ordinateur : vers une théorie des TIC en éducation

    Directory of Open Access Journals (Sweden)

    François Desjardins

    2005-02-01

    Full Text Available Depuis plusieurs années, dans la littérature, on peut sentir un besoin de préciser l’ensemble de connaissances et de compétences relatives aux ordinateurs nécessaires à l’enseignement et à l’apprentissage. Dans ce contexte, cette recherche vise à développer un modèle global qui permettrait de classer à la fois les outils, leurs usages, leurs incidences ainsi que les connaissances et compétences impliquées dans l’intégration des TIC en éducation de façon à pouvoir comprendre les diverses relations qui existent entre chacune de ces composantes. Une première opérationnalisation de ce modèle a donné lieu au développement d’un instrument permettant de recueillir les représentations des enseignants quant à leurs compétences. Cet article présente le modèle élaboré, le questionnaire qui en a découlé et les résultats des premières analyses statistiques des profils recueillis auprès de plus de 600 enseignants francophones de l’Ontario.

  9. Photodegradation and toxicity changes of antibiotics in UV and UV/H2O2 process

    International Nuclear Information System (INIS)

    Yuan Fang; Hu Chun; Hu Xuexiang; Wei Dongbin; Chen Yong; Qu Jiuhui

    2011-01-01

    The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H 2 O 2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H 2 O 2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV , defined as the experimentally determined ·OH radical exposure per UV fluence. The R OH,UV values represent the background ·OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H 2 O 2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H 2 O 2 process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H 2 O 2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of ·OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H 2 O 2 process would be determined by parent compound degradation and toxicity changes.

  10. A study on UV irradiated HDPE

    International Nuclear Information System (INIS)

    Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

    2006-01-01

    The structure and properties of HDPE irradiated by ultraviolet (UV) in ozone atmosphere were studied by FT-IR, XPS, gel, and water contact angle test. The oxygen-containing groups such as C=O, C-O and C(=O)O were introduced onto high density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, their content increased with the UV irradiation time. Under the same UV irradiation conditions, amount of the oxygen-containing groups introduced in ozone atmosphere was more than that in air atmosphere, indicating that the speed of oxygen-containing groups introduced through UV irradiation in ozone atmosphere was faster than that in air. Therefore, HDPE could be quickly functionalized through UV irradiation in ozone atmosphere. There was no gel formed in the HDPE irradiated in ozone atmosphere. After UV irradiation, the water contact angle of HDPE decreased, and its hydrophilicity was improved, suggesting that the compatibility between the irradiated HDPE and polar polymer or inorganic fillers may be better. Compared with HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The structure and properties of irradiated HDPE/CaCO 3 blend were also investigated. The results showed that the compatibility and interfacial action of the irradiated HDPE/CaCO 3 blend were improved compared to that of HDPE/CaCO 3 blend. The mechanical properties of irradiated HDPE/CaCO 3 blend increased with increasing irradiation time. (authors)

  11. Impact of fouling on UV effectiveness

    International Nuclear Information System (INIS)

    Dykstra, T.S.; Chauret, C.

    2002-01-01

    In recent years ultraviolet light has gained in popularity as an attractive disinfection alternative due to its ability to inactivate bacteria and viruses. UV light has the potential to inactivate Cryptosporidium parvum and Giardia lamblia with a very low potential for the formation of harmful disinfection by-products. Previous studies have reported that particulate material present in the water can act to reduce the exposure of UV light to the receiving waters and that the interference of organic particles can serve to protect bacteria and viruses from intended disinfection. Disinfection capacity can also be reduced by organics in the source water that can accumulate on the surface of quartz sleeves. The purpose of this study was to determine the ability of a medium pressure UV light, at drinking water treatment levels, to inactivate MS 2 bacteriophage after a quartz tube has been fouled with organic rich source water for a 12- week period. To this end the inactivation of MS 2 was determined under clean and fouled conditions, in the presence and absence of humic rich water. The effect of lamp age on inactivation was also investigated. The results suggest that organic fouling of a quartz tube has a significant impact on the disinfection capacity of a medium pressure UV lamp. The presence of organics in the source water also plays a significant role in reducing the capacity of UV for bacterial and viral disinfection. Lamp age also seems to have some effect on the efficiency of UV disinfection. (author)

  12. Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

    Science.gov (United States)

    Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

    2009-02-01

    Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

  13. Effects of UV radiation on phytoplankton

    Science.gov (United States)

    Smith, Raymond C.; Cullen, John J.

    1995-07-01

    It is now widely documented that reduced ozone will result in increased levels of ultraviolet (UV) radiation, especially UV-B (280-320nm), incident at the surface of the earth [Watson, 1988; Anderson et al., 1991; Schoeberl and Hartmann, 1991; Frederick and Alberts, 1991; WMO, 1991; Madronich, 1993; Kerr and McElroy, 1993], and there is considerable and increasing evidence that these higher levels of UV-B radiation may be detrimental to various forms of marine life in the upper layers of the ocean. With respect to aquatic ecosystems, we also know that this biologically- damaging mid-ultraviolet radiation can penetrate to ecologically- significant depths in marine and freshwater systems [Jerlov, 1950; Lenoble, 1956; Smith and Baker, 1979; Smith and Baker, 1980; Smith and Baker, 1981; Kirk et al., 1994]. This knowledge, plus the dramatic decline in stratospheric ozone over the Antarctic continent each spring, now known to be caused by anthropogenically released chemicals [Solomon, 1990; Booth et al., 1994], has resulted in increased UV-environmental research and a number of summary reports. The United Nations Environmental Program (UNEP) has provided recent updates with respect to the effects of ozone depletion on aquatic ecosystems (Hader, Worrest, Kumar in UNEP 1989, 1991, Hader, Worrest, Kumar and Smith UNEP 1994) and the Scientific Committee on Problems of the Environment (SCOPE) has provided [SCOPE, 1992] a summary of the effects of increased UV radiation on biological systems. SCOPE has also reported [SCOPE, 1993] on the effects of increased UV on the biosphere. In addition, several books have recently been published reviewing various aspects of environmental UV photobiology [Young et al., 1993], UV effects on humans, animals and plants [Tevini, 1993], the biological effects of UV radiation in Antarctica [Weiler and Penhale, 1994], and UV research in freshwater ecosystems [Williamson and Zagarese, 1994]. Several other reviews are relevant [NAS, 1984; Caldwell

  14. Facteurs environnementaux associés au trouble du spectre de l’autisme : étude de délimitation portant sur les années 2003 à 2013

    Directory of Open Access Journals (Sweden)

    Michelle Ng

    2017-01-01

    Full Text Available Introduction : Le nombre d’enfants chez lesquels on diagnostique un trouble du spectre de l’autisme (TSA grimpe rapidement depuis une décennie. L’étiologie de ce trouble est toutefois en grande partie inconnue, même si la contribution de l’environnement est importante par rapport à celle de la génétique. Nous avons procédé à une étude de délimitation pour évaluer en détail l’état actuel des connaissances sur les facteurs environnementaux présents depuis le stade de la préconception jusqu’au début de la vie que l’on associe au TSA et pour dégager les lacunes de la recherche. Méthodologie : Nous avons cherché dans les bases de données électroniques MEDLINE, PsycINFO et ERIC des articles portant sur des facteurs de risque potentiels ou des facteurs de protection des environnements physiques et sociaux associés au TSA et à ses sous-catégories entre le 1er janvier 2003 et le 12 juillet 2013. Nous avons regroupé les articles en thèmes généraux en fonction de l’exposition environnementale : facteurs chimiques, physiologiques, nutritionnels et sociaux. Résultats : Nous avons trouvé plus de 50 000 publications, mais après élimination des études inadmissibles il est resté 315 articles. La plupart de ces études portaient sur les facteurs psychologiques, suivis de près par les facteurs chimiques et, à un degré beaucoup moindre, les facteurs nutritionnels et sociaux associés au TSA. En dépit d’une masse importante de publications et de nombreuses études hétérogènes, quelques facteurs de risque se sont démarqués régulièrement : facteurs chimiques comme les polluants atmosphériques causés par la circulation; facteurs physiologiques, dont l’âge avancé des parents, les naissances prématurées, l’insuffisance de poids à la naissance, l’hyperbilirubinémie et les grappes de complications de la grossesse et enfin le statut de la mère vis-à-vis de l’immigration. En dépit de

  15. Les adhésifs à photopolymérisation radicalaire employés pour le cpllage structural du verre en conservation-restauration: Etude de la résistance au cisaillement de 4 adhésifs optiques polymérisables aux UV

    OpenAIRE

    Gillioz, Sandra,

    2016-01-01

    Les adhésifs photopolymérisables, dont la prise s’effectue en quelques secondes sous rayonnement ultraviolet (UV), représentent une option séduisante pour le collage du verre en conservationrestauration, particulièrement lorsque les fragments ne peuvent être maintenus de manière temporaire. Dans le présent travail, nous avons étudié la compatibilité des adhésifs photopolymérisables avec le collage du verre en conservation-restauration en nous focalisant sur leur résistance mécanique. Quatre a...

  16. Optimizing UV Index determination from broadband irradiances

    Science.gov (United States)

    Tereszchuk, Keith A.; Rochon, Yves J.; McLinden, Chris A.; Vaillancourt, Paul A.

    2018-03-01

    A study was undertaken to improve upon the prognosticative capability of Environment and Climate Change Canada's (ECCC) UV Index forecast model. An aspect of that work, and the topic of this communication, was to investigate the use of the four UV broadband surface irradiance fields generated by ECCC's Global Environmental Multiscale (GEM) numerical prediction model to determine the UV Index. The basis of the investigation involves the creation of a suite of routines which employ high-spectral-resolution radiative transfer code developed to calculate UV Index fields from GEM forecasts. These routines employ a modified version of the Cloud-J v7.4 radiative transfer model, which integrates GEM output to produce high-spectral-resolution surface irradiance fields. The output generated using the high-resolution radiative transfer code served to verify and calibrate GEM broadband surface irradiances under clear-sky conditions and their use in providing the UV Index. A subsequent comparison of irradiances and UV Index under cloudy conditions was also performed. Linear correlation agreement of surface irradiances from the two models for each of the two higher UV bands covering 310.70-330.0 and 330.03-400.00 nm is typically greater than 95 % for clear-sky conditions with associated root-mean-square relative errors of 6.4 and 4.0 %. However, underestimations of clear-sky GEM irradiances were found on the order of ˜ 30-50 % for the 294.12-310.70 nm band and by a factor of ˜ 30 for the 280.11-294.12 nm band. This underestimation can be significant for UV Index determination but would not impact weather forecasting. Corresponding empirical adjustments were applied to the broadband irradiances now giving a correlation coefficient of unity. From these, a least-squares fitting was derived for the calculation of the UV Index. The resultant differences in UV indices from the high-spectral-resolution irradiances and the resultant GEM broadband irradiances are typically within 0

  17. Influence of uvA on the erythematogenic and therapeutic effects of uvB irradiation in psoriasis; photoaugmentation effects

    International Nuclear Information System (INIS)

    Boer, J.; Schothorst, A.A.; Suurmond, D.

    1981-01-01

    The effect of repeated exposure to an additive dose of long ultraviolet (uvA) radiation on the erythemogenic and therapeutic effects of middle ultraviolet (uvB) irradiation was investigated in 8 patients with psoriasis. The surface of the backs of these patients was divided into 2 parts, 1 of which received only uvB irradiation 4 times a week and the other uvA + uvB. uvB was provided by Philips TL-12 lamps and uvA by glass-filtered Philips TL-09 lamps. uvA was held constantly at 10 J/cm2, whereas uvB alone were evaluated by 4 tests during the treatment to determine the minimal erythema dose (MED). Test I (at the start of the therapy) showed a photoaugmentative effect which was no longer apparent in Test III (third week). Test III showed a reversal of the ratios of the MEDs of the sites irradiated with the uvA + uvB and uvB (MED A + B/MED B). This is ascribed to the marked pigmentation which appeared after repeated irradiation with the uvA + uvB combination. Comparison showed for the improvement of the psoriasis no distinct differences between uvA + uvB irradiation and uvB alone, but the former had the cosmetic advantage of giving pleasing tan

  18. La constitution du capital social. Comment les entreprises innovantes françaises financent-elles leur création ? Gathering Social Capital. How do Innovative French Companies finance their Creation ?

    Directory of Open Access Journals (Sweden)

    Régis Moreau

    2011-03-01

    Full Text Available Les entreprises innovantes, plus que les autres entreprises, ont besoin d’importantes sommes d’argent pour se développer. C’est pourquoi la constitution de leur capital social est une opération essentielle puisque ce dernier représente leur première source de financement. D’ailleurs, il est avéré que son montant influence les chances de survie de l’entreprise. Pourtant, peu d’études ont interrogé les processus concrets d’association entre les entrepreneurs et leurs actionnaires initiaux. Comment les créateurs forment-ils leur actionnariat initial ? Quels sont les mécanismes sociologiques qui interviennent ? Pour répondre à ces questions, nous avons rencontré les créateurs de 45 entreprises innovantes ainsi que leurs actionnaires. Au fil d’un travail empirique, une hypothèse a émergé : la circulation de l’argent apporté par les actionnaires initiaux est assujettie à la confrontation des logiques de chacune des parties. C’est donc une analyse plus qualitative que quantitative qui décide de la diffusion et de la recevabilité des fonds pour la création de ce type d’entreprises.Innovative companies, more than any others, need large sums of money to start-up. That is why the constitution of their social capital is an essential operation since it represents their first source of funds. Moreover, it has been shown that its amount influences the company's chances of survival. However, few studies have looked into the concrete processes of association between the initial entrepreneurs and their shareholders. How do the creators form their initial shareholding ? What are the sociological mechanisms intervening ? To answer these questions, we met with the creators of 45 innovative companies as well as their shareholders. As the conclusion of research work, a hypothesis has emerged : the circulation of funds provided by the initial shareholders is subject to a confrontation of the logics of each of the

  19. Monitoring and control of UV and UV-TiO2 disinfections for municipal wastewater reclamation using artificial neural networks

    International Nuclear Information System (INIS)

    Lin, Chuang-Hung; Yu, Ruey-Fang; Cheng, Wen-Po; Liu, Chun-Ru

    2012-01-01

    Highlights: ► ANN models can effectively control both UV and UV-TiO 2 disinfections for wastewater reuse. ► Comparing to UV disinfection, UV-TiO 2 disinfection can save 13.2–15.7% of UV dosage and capacity. ► SS decreases disinfection efficiency when UV doses were 2 . - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO 2 can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO 2 disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO 2 disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO 2 disinfections. A novel ANN control strategy is applied to control UV and UV-TiO 2 disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO 2 disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO 2 disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2–15.7%.

  20. The UV Sensor Onboard the Mars Science Laboratory Mission: Correction and Generation of UV Fluxes

    Science.gov (United States)

    Vicente-Retortillo, Á.; Martinez, G.; Renno, N. O.; Lemmon, M. T.; Gomez-Elvira, J.

    2017-12-01

    The Rover Environmental Monitoring Station UV sensor (UVS) onboard the Mars Science Laboratory mission has completed more than 1750 sols of measurements, providing an unprecedented coverage ranging from diurnal to interannual times scales [1,2]. The UVS is comprised of six photodiodes to measure the UV flux in the ranges 200-380, 320-380, 280-320, 200-280, 230-290 and 300-350 nm [3]. UV fluxes in units of W/m2 can be found in the NASA Planetary Data System (PDS). However, dust deposition on the UVS and a non-physical discontinuity in the calibration functions when the solar zenith angle is above 30º cause errors in these fluxes that increase with time. We have developed a technique to correct UV fluxes from the effects of dust degradation and inconsistencies in the angular response of the UVS. The photodiode output currents (available in the PDS as lower-level TELRDR products), ancillary data records (available in the PDS as ADR products) and dust opacity values derived from Mastcam observations are used for performing the corrections. The corrections have been applied to the UVA band (320-380 nm) for the first 1000 sols of the mission, providing excellent results [4]. We plan to correct the UV fluxes on each of the six UVS bands and to make these results available in the PDS. Data products generated by this study will allow comparisons of the UV radiation environment at Gale crater with that at the locations of the future missions ExoMars 2020 and Mars 2020, as well as the assessment of the potential survivability of biological contaminants brought to Mars from Earth. References: [1] Smith, M. D., et al. (2016), Aerosol optical depth as observed by the Mars Science Laboratory REMS UV photodiodes, Icarus, 280, 234-248. [2] Vicente-Retortillo, Á., et al. (2017), Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements, Geophys. Res. Lett., 44, 3502-3508. [3] Gómez-Elvira, J., et al. (2012), REMS: The environmental sensor

  1. Mechanisms of uv mutagenesis in yeast

    International Nuclear Information System (INIS)

    Lawrence, C.W.; Christensen, R.; Schwartz, A.

    1982-01-01

    The uv mutagenesis in yeast depends on the function of the RAD6 locus, a gene that is also responsible for a substantial fraction of wild-type resistance, suggesting that this eukaryote may possess a misrepair mechanism analogous to that proposed for Escherichia coli. The molecular mechanism responsible for RAD6 repair or recovery is not yet known, but it is different from either excision or recombination-dependent repair, processes carried out by the other two main repair pathways in yeast. RAD6-dependent mutagenesis has been found to have the following characteristics. It is associated at best with only a small fraction of RAD6-dependent repair, the majority of the sensitivity of rad6 mutants being due to their lack of nonmutagenic repair. SRS2 metabolic suppressors restore a substantial fraction of uv resistance to rad6 mutants but do not restore their uv mutability. Strains containing mutations at loci (rev, umr) that are probably more directly involved in mutagenesis are only mildly sensitive, and there is a poor correlation between their sensitivity and mutational deficiency. The uv mutagenesis appears to require a large number of gene functions, perhaps ten or more. Where examined in detail, these genes have been found to be concerned in the production of only a specific range of mutational events, not all of them. Mating experiments have shown that a substantial fraction, probably 40% or more, of uv-induced mutations are untargeted, that is, occur in lesion-free regions of DNA. The uv irradiation, therefore, produces a general reduction in the normally high fidelity with which DNA is replicated on undamaged templates. It does not appear to be necessary for the causal lesion to be present in the same chromosome as the mutation it induces. The reduction in fidelity may be the consequence of the production of a diffusible factor in uv-irradiated cells, but definite evidence supporting this proposal has not yet been obtained

  2. Les victimes silencieuses des crises humanitaires et l’(insécurité de leurs activités économiques : Etude de cas parmi les migrants de deux villes tchadiennes

    Directory of Open Access Journals (Sweden)

    Syntyche Nakar Djindil

    2009-04-01

    Full Text Available Lorsqu’une catastrophe humanitaire fait la une des médias, la communauté internationale se mobilise à réduire les conséquences les plus sérieuses. La population du Tchad connaît cependant des crises endémiques qui ne sont liées à aucun élément déclencheur particulier# ; elle ne reçoit pas l’assistance internationale nécessaire pour faire face à ces problèmes. La présente étude concerne 111 ménages de migrants de la région du centre du Tchad, qui ont, à cause de la guerre et de la sécheresse, tout perdu, et qui vivent désormais dans de N’Djamena et de Mongo#; ces familles sont confrontées à la précarité et à d’autres éléments qui menacent leurs moyens de subsistance. Des méthodes qualitatives et quantitatives ont été combinées dans l’étude pour révéler l’histoire intrigante de leur vie quotidienne au milieu de crises complexes et endémiques. Des données anthropométriques et sanitaires ont été utilisées pour déterminer l’état nutritionnel des mères et de leurs enfants de moins de cinq ans. Des narrations de vie, des entretiens en profondeur et des observations participatives ont permis aux chercheurs de déterminer les stratégies de négociation que ces familles adoptent pour accéder à leur nourriture et à leurs abris, leur expérience de l’insécurité alimentaire et de la vulnérabilité sanitaire, ainsi que les conséquences que ces éléments ont sur leur vie quotidienne. Les résultats indiquent que 62% des ménages sont dirigés par des femmes, qu’il existe de forts taux de malnutrition aiguë (40-50% et chronique (35-40% et que 46% des mères sont sous-alimentées et anémiées. Les taux de mortalité infantile se sont avérés également élevés#: de 30% à 42%. 97% des enfants n’ont pas été complètement vaccinés, voire pas vaccinés du tout, dans certains cas. Aucun des ménages n’a accès à l’eau potable et aux services sociaux de base. La corruption end

  3. Use of satellite erythemal UV products in analysing the global UV changes

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2011-09-01

    Full Text Available Long term changes in solar UV radiation affect global bio-geochemistry and climate. The satellite-based dataset of TOMS (Total Ozone Monitoring System and OMI (Ozone Monitoring Instrument of erythemal UV product was applied for the first time to estimate the long-term ultraviolet (UV changes at the global scale. The analysis of the uncertainty related to the different input information is presented. OMI and GOME-2 (Global Ozone Monitoring Experiment-2 products were compared in order to analyse the differences in the global UV distribution and their effect on the linear trend estimation.

    The results showed that the differences in the inputs (mainly surface albedo and aerosol information used in the retrieval, affect significantly the UV change calculation, pointing out the importance of using a consistent dataset when calculating long term UV changes. The areas where these differences played a major role were identified using global maps of monthly UV changes. Despite the uncertainties, significant positive UV changes (ranging from 0 to about 5 %/decade were observed, with higher values in the Southern Hemisphere at mid-latitudes during spring-summer, where the largest ozone decrease was observed.

  4. The World Space Observatory Ultraviolet (WSO-UV), as a bridge to future UV astronomy

    Science.gov (United States)

    Shustov, B.; Gómez de Castro, A. I.; Sachkov, M.; Vallejo, J. C.; Marcos-Arenal, P.; Kanev, E.; Savanov, I.; Shugarov, A.; Sichevskii, S.

    2018-04-01

    Ultraviolet (UV) astronomy is a vital branch of space astronomy. Many dozens of short-term UV-experiments in space, as well as long-term observatories, have brought a very important knowledge on the physics and chemistry of the Universe during the last decades. Unfortunately, no large UV-observatories are planned to be launched by most of space agencies in the coming 10-15 years. Conversely, the large UVOIR observatories of the future will appear not earlier than in 2030s. This paper briefly describes the projects that have been proposed by various groups. We conclude that the World Space Observatory-Ultraviolet (WSO-UV) will be the only 2-m class UV telescope with capabilities similar to those of the HST for the next decade. The WSO-UV has been described in detail in previous publications, and this paper updates the main characteristics of its instruments and the current state of the whole project. It also addresses the major science topics that have been included in the core program of the WSO-UV, making this core program very relevant to the current state of the UV-astronomy. Finally, we also present here the ground segment architecture that will implement this program.

  5. Ozone layer - climate change interactions. Influence on UV levels and UV related effects

    NARCIS (Netherlands)

    Kelfkens G; Bregman A; de Gruijl FR; van der Leun JC; Piquet A; van Oijen T; Gieskes WWC; van Loveren H; Velders GJM; Martens P; Slaper H; NOP; LPI; LLO

    2002-01-01

    Ozone in the atmosphere serves as a partially protective filter against the most harmful part of the solar UV-spectrum. Decreases in ozone lead to increases in ambient UV with a wide variety of adverse effects on human health, aquatic and terrestrial ecosystems and food chains. Human health

  6. Study of High-Resolution Spectroscopy of Plutonium. Part I. Contribution to the Classification of the Arc Spectrum. Part II. Determination of the Magnetic Moment of {sup 239}Pu; Etude du plutonium par spectroscopie a haute resolution: contribution a la classification du spectre d'arc et determination du moment magnetique de {sup 239}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenkorn, S

    1962-07-01

    The study of the hyperfine structure and isotope shift enabled the positions of the first five levels of the multiplet {sup 7}F{sub 0-6} belonging to the fundamental configuration 5f{sup 6}7s{sup 2} to be determined. The classification of the arc spectrum begun in this way led to 25 odd levels, the number of classified lines (70) representing about 30 p. 100 of the light emitted by this hollow cathode in the visible. In addition, the isotope shifts of many lines and the data given by the King furnace show that the first levels of the configuration 5f{sup 5}6d7s{sup 2} are also low less than 8000 cm{sup -1} above the fundamental level {sup 7}F{sub 0}. The proximity of the configuration f{sup 6}s{sup 2} and f{sup 5}ds{sup 2} shows that the bonding energies of the 5f and 6d electrons are of the same order of magnitude and this fact must be responsible for the multiple valences belonging to plutonium. From the hyperfine structure of spark lines (Pu II) the interval factor a{sub 7} for the electron was deduced giving for the calculated nuclear moment of {sup 239}Pu a value of +0.21 {+-}0.06 {mu}{sub N}. The position of the hyperfine components show that the nuclear moment is positive, although the theoretical value given by B. R. Mottelson and S. Nillson is negative and equal to -0.1 {mu}{sub N}. (author) [French] Partie 1 - L'etude des structures hyperfines et du deplacement isotopique des raies du spectre d'arc du plutonium a permis de determiner la position des cinq premiers niveaux du multiplet {sup 7}F{sub 0-6} correspondant a la configuration fondamentale 5f{sup 6}7s{sup 2}. Des lors, la classification du spectre d'arc du plutonium pouvait etre amorcee: 25 niveaux impairs ont ete mis en evidence et le nombre de raies classees (70) represente environ 30 p. 100 de l'intensite totale du spectre d'arc emis par une cathode creuse dans le visible. D'autre part, le deplacement isotopique de certaines raies, joint aux renseignements donnes par le spectre emis par le four

  7. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  8. UV Catalysis, Cyanotype Photography, and Sunscreens

    Science.gov (United States)

    Lawrence, Glen D.; Fishelson, Stuart

    1999-09-01

    This laboratory experiment is intended for a chemistry course for non-science majors. The experiment utilizes one of the earliest photographic processes, the cyanotype process, to demonstrate UV catalysis of chemical reactions. In addition to making photographic prints from negatives, the process can be used to test the effectiveness of sunscreens and the relative efficacy of the SPF (sun protection factor) rating of sunscreens. This is an inexpensive process, requiring solutions of ammonium ferric citrate and potassium ferricyanide, with options to use hydrogen peroxide and ammonium hydroxide solutions. Students can prepare their own UV-sensitized paper with the indicated chemicals and watch the photographic image appear as it is exposed to sunlight or fluorescent UV lamps in a light box designed for use in this experiment. The laboratory experiment should stimulate discussion of UV catalysis, photographic processes and photochemistry, sunscreens, and UV damage to biological organisms. The chemicals used are relatively nontoxic, and the procedure is simple enough to be used by groups of diverse ages and abilities.

  9. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation on growth of cucumber

    International Nuclear Information System (INIS)

    Krizek, D.T.; Mirecki, R.M.; Britz, S.J.

    1997-01-01

    The influence of solar UV-A and UV-B radiation at Beltsville, Maryland, on growth and flavonoid content in four cultivars of Cucumis sativus L. (Ashley, Poinsett, Marketmore, and Salad Bush cucumber) was examined during the summers of 1994 and 1995. Plants were grown from seed in UV exclusion chambers consisting of UV-transmitting Plexiglas, lined with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or cellulose acetate to transmit UV-A and UV-B. Despite previously determined differences in sensitivity to supplemental UV-B radiation, all four cultivars responded similarly to UV-B exclusion treatment. After 19–21 days, the four cultivars grown in the absence of solar UV-B (polyester) had an average of 34, 55, and 40% greater biomass of leaves, stems, and roots, respectively, 27% greater stem height, and 35% greater leaf area than those grown under ambient UV-B (cellulose acetate). Plants protected from UV-A radiation as well (Llumar) showed an additional 14 and 22% average increase, respectively, in biomass of leaves and stems, and a 22 and 19% average increase, respectively, in stem elongation and leaf area over those grown under polyester. These findings demonstrate the extreme sensitivity of cucumber not only to present levels of UV-B but also to UV-A and suggest that even small changes in ozone depletion may have important biological consequences for certain plant species. (author)

  10. Numerical and experimental investigation of UV disinfection for water treatment

    International Nuclear Information System (INIS)

    Li, H.Y.; Osman, H.; Kang, C.W.; Ba, T.

    2017-01-01

    Highlights: • UV irradiation for water treatment is numerically and experimentally investigated. • Fluence rate E increases exponentially with the increase of UVT. • UV dose distribution moves to a high range with increase of UVT and lamp power. • A linear relationship is observed between fluence rate E and average UV dose D_a_v_e. • D_a_v_e decreases with the increase of UVT and fluid flow rate. - Abstract: Disinfection by ultraviolet (UV) for water treatment in a UV reactor is numerically and experimentally investigated in this paper. The flow of water, UV radiation transportation as well as microorganism particle trajectories in the UV reactor is simulated. The effects of different parameters including UV transmittance (UVT), lamp power and water flow rate on the UV dose distribution and average UV dose are studied. The UV reactor performance in terms of average UV dose under these parameters is analysed. Comparisons are made between experiments and simulations on the average UV dose and reasonable agreement is achieved. The results show that the fluence rate increases exponentially with the increase of UVT. The UV dose distribution profiles moves to a high range of UV dose with the increase of UVT and lamp power. The increase of water flow rate reduces the average exposure time of microorganism particles to the UV light, resulting in the shifting of UV dose distribution to a low range of UV dose. A linear relationship is observed between fluence rate and the average UV dose. The average UV dose increases with the increase of lamp power while it decreases with the increase of UVT and water flow rate.

  11. Tekstilde Uv Absorban Madde Uygulamaları The Applications of UV Absorber on Textiles

    OpenAIRE

    MERDAN, Nigar; ACAR, Kamil

    2009-01-01

    Tekstiller UV radyasyonuna karşı koruma sağlarken, bu aşamada radyasyonun dozu da önem taşımaktadır. Bu nedenle tekstil materyallerine UV absorban maddeler, liflerin üretimi esnasında ya da bitim işlemlerinde uygulanmaktadır. UV absorban maddelerin kullanılmasıyla, tekstil ürünlerinde UV ışınlarının geçirgenliğinin yoğunluk derecesi azaltılır. UV absorbanları, materyale gelen ışık tarafından oluşan olumsuz etkileri engeller

  12. Patterning of nanoparticulate transparent conductive ITO films using UV light irradiation and UV laser beam writing

    International Nuclear Information System (INIS)

    Solieman, A.; Moharram, A.H.; Aegerter, M.A.

    2010-01-01

    Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency (∼85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ□.

  13. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    Energy Technology Data Exchange (ETDEWEB)

    Silva Filho, F C; Elias, C A; Souza, W de

    1986-05-01

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells.

  14. UV SEDs of early-type cluster galaxies: a new look at the UV upturn

    Science.gov (United States)

    Ali, S. S.; Bremer, M. N.; Phillipps, S.; De Propris, R.

    2018-05-01

    Using GALEX, Ultraviolet Optical Telescope (UVOT), and optical photometry, we explore the prevalence and strength of the Ultraviolet (UV) upturn in the spectra of quiescent early-type galaxies in several nearby clusters. Even for galaxies with completely passive optical colours, there is a large spread in vacuum UV colour consistent with almost all having some UV upturn component. Combining GALEX and UVOT data below 3000 Å, we generate for the first time comparatively detailed UV spectral energy distributions for Coma cluster galaxies. Fitting the UV upturn component with a blackbody, 26 of these show a range of characteristic temperatures (10 000-21 000K) for the UV upturn population. Assuming a single temperature to explain GALEX-optical colours could underestimate the fraction of galaxies with UV upturns and mis-classify some as systems with residual star formation. The UV upturn phenomenon is not an exclusive feature found only in giant galaxies; we identify galaxies with similar (or even bluer) FUV - V colours to the giants with upturns over a range of fainter luminosities. The temperature and strength of the UV upturn are correlated with galaxy mass. Under the plausible hypothesis that the sources of the UV upturn are blue horizontal branch stars, the most likely mechanism for this is the presence of a substantial (between 4 per cent and 20 per cent) Helium-rich (Y > 0.3) population of stars in these galaxies, potentially formed at z ˜ 4 and certainly at z > 2; this plausibly sets a lower limit of {˜ } {0.3- 0.8} × 10^{10} M⊙ to the in situ stellar mass of ˜L* galaxies at this redshift.

  15. Influence de la nature des fuels lourds sur la qualité de leur combustion Influence of Heavy Fuel Oil Composition on Particulate Emissions

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available A partir d'études de combustion de fuels lourds numéro 2 effectuées dans une chaudière de 1 MW et dans un foyer de 0,1 MW, on conclut que le résidu de Carbone Conradson (CCR des fuels est un bon indicateur de leur combustibilité, mais qu'il n'est pas suffisant dans tous les cas, c'est-à-dire que pour un même CCR, on peut mesurer des valeurs différentes en indice pondéral. Plusieurs interpréta. tions possibles ont été proposées et vérifiées : a Le résidu de Carbone Conradson, résultat d'une pyrolyse lente, est une procédure qui n'est pas suffisamment représentative des conditions réelles. Or, en soumettant un certain nombre de fuels à une pyrolyse flash (technique de la grille chauffée, on observe une bonne corrélation entre la quantité de résidu résultant et le CCR. Donc, ce dernier reste un bon indicateur de combustibilité. b Pour les fuels ex résidu atmosphérique, ex résidu sous-vide et ex désasphaltage, on détermine de satisfaisantes corrélations entre le CCR et certaines caractéristiques physico-chimiques de la fraction lourde des fuels (point de coupe choisi 450°C : polyaromaticité (mesurée par RMN du Carbone 13, C/H, masse moléculaire. Cependant, les fuels de visco-réduction satisfont à d'autres corrélations, de même que les résidus de vapocraquage. Donc, pour ces classes de fuels, on peut prévoir des anomalies entre indice pondéral et CCR, ce qui est observé dans certains équipements. c On observe que pour une même valeur de CCR, la proportion relative entre fractions légères et fractions lourdes des fuels peut parfois varier très sensiblement avec pour conséquence des modifications dans les cartes de richesse et de température des flammes résultantes, et donc des variations dans les émissions particulaires. L'importance de telles variations dépendra des types de brûleurs et de chambres de combustion dans lesquelles la flamme se développera. On the basis of combustion runs of

  16. EB/UV curing market in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Khairul Zaman; Nik Salleh, Nik Ghazali; Mahmood, Mohd Hilmi [Malaysian Inst. for Nuclear Technology Res. (MINT), Bangi (Malaysia)

    1999-07-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing ofprinting ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films.

  17. EB/UV curing market in Malaysia

    International Nuclear Information System (INIS)

    Khairul Zaman Dahlan; Nik Ghazali Nik Salleh; Mohd Hilmi Mahmood

    1999-01-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing of printing ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films

  18. Putative Enzymes of UV Photoproduct Repair

    Directory of Open Access Journals (Sweden)

    Cynthia J. Sakofsky

    2011-01-01

    Full Text Available In order to determine the biological relevance of two S. acidocaldarius proteins to the repair of UV photoproducts, the corresponding genes (Saci_1227 and Saci_1096 were disrupted, and the phenotypes of the resulting mutants were examined by various genetic assays. The disruption used integration by homologous recombination of a functional but heterologous pyrE gene, promoted by short sequences attached to both ends via PCR. The phenotypic analyses of the disruptants confirmed that ORF Saci_1227 encodes a DNA photolyase which functions in vivo, but they could not implicate ORF Saci_1096 in repair of UV- or other externally induced DNA damage despite its similarity to genes encoding UV damage endonucleases. The success of the gene-disruption strategy, which used 5′ extensions of PCR primers to target cassette integration, suggests potential advantages for routine construction of Sulfolobus strains.

  19. Quantification of biologically effective environmental UV irradiance

    Science.gov (United States)

    Horneck, G.

    To determine the impact of environmental UV radiation on human health and ecosystems demands monitoring systems that weight the spectral irradiance according to the biological responses under consideration. In general, there are three different approaches to quantify a biologically effective solar irradiance: (i) weighted spectroradiometry where the biologically weighted radiometric quantities are derived from spectral data by multiplication with an action spectrum of a relevant photobiological reaction, e.g. erythema, DNA damage, skin cancer, reduced productivity of terrestrial plants and aquatic foodweb; (ii) wavelength integrating chemical-based or physical dosimetric systems with spectral sensitivities similar to a biological response curve; and (iii) biological dosimeters that directly weight the incident UV components of sunlight in relation to the effectiveness of the different wavelengths and to interactions between them. Most biological dosimeters, such as bacteria, bacteriophages, or biomolecules, are based on the UV sensitivity of DNA. If precisely characterized, biological dosimeters are applicable as field and personal dosimeters.

  20. UV-induced structural changes in chromatin

    International Nuclear Information System (INIS)

    Lang, H.; Zimmer, C.; Vengerov, Yu.Yu.

    1985-01-01

    UV-induced structural alterations of chromatin were studied by means of CD, electron microscopic, and gel electrophoretic measurements. The results indicate that chromatin undergoes serious structural changes after irradiation even at very low fluences. In the low fluence range the structural transitions from the higher ordered chromatin structure to the unfolded state occur without detectable changes in the content of histone H1 and of the core histones. Histone H1 disappears only at fluences above 10 kJ/m 2 . Furthermore, DNA in chromatin is much more sensitive against UV-irradiation and shows a higher degree of strand scission relative to free DNA. While fragmentation in free DNA occurs at fluences above 15 kJ/m 2 , it occurs even at 5.5 kJ/m 2 in the case of chromatin. The biological meaning of the observed UV-induced structural alterations of chromatin is discussed. (author)

  1. UV-LIGA: From Development to Commercialization

    Directory of Open Access Journals (Sweden)

    Grégoire Genolet

    2014-07-01

    Full Text Available A major breakthrough in UV-LIGA (Lithographie, Galvanoformung and Abformung started with the use of epoxy-based EPON® SU-8 photoresist in the mid-1990s. Using this photoresist has enabled the fabrication of tall and high aspect ratio structures without the use of a very expensive synchrotron source needed to expose the photoresist layer in X-ray LIGA. SU-8 photoresist appeared to be well-suited for LIGA templates, but also as a permanent material. Based on UV-LIGA and SU-8, Mimotec SA has developed processes to manufacture mold inserts and metallic components for various market fields. From one to three-level parts, from Ni to other materials, from simple to complicated parts with integrated functionalities, UV-LIGA has established itself as a manufacturing technology of importance for prototyping, as well as for mass-fabrication. This paper reviews some of the developments that led to commercial success in this field.

  2. Overview of UV and EB curing

    International Nuclear Information System (INIS)

    Garnett, J.L.

    2000-01-01

    Full text: UV and EB are complementary techniques in radiation curing. In the proposed paper, a brief review of both fields will be given. This will include principles of the process, the chemistry of the systems including monomers/oligomers/polymers used, additives required where necessary such as photoinitiators for UV, flow aids, adhesion promoters and the like. The types of equipment used in such processes will also be discussed including low energy electron beam utilisation and excimer curing. The advantages and disadvantages of both techniques will be examined. Mechanistic aspects of both curing systems will be discussed. Applications of the technology including developments in the banknote printing field will be summarised

  3. UV line emission of symbiotic stars

    International Nuclear Information System (INIS)

    Nussbaumer, H.

    1982-01-01

    General characteristics of emission line spectra from symbiotic stars are outlined. Data from some special line ratios in the 1000 A - 3000 A range, and others connecting the visual and the far UV lines are presented, and their application to symbiotic stars is discussed. Integrated fractional abundances for ions easily observed in the far UV are given to facilitate abundance determinations for nebular conditions. It is found that the physical conditions of the regions emitting the emission line spectra differ considerably among different symbiotic stars. (Auth.)

  4. /UV Synergistic Aging of Polyester Polyurethane Film Modified by Composite UV Absorber

    Directory of Open Access Journals (Sweden)

    Yanzhi Wang

    2013-01-01

    Full Text Available The pure polyester polyurethane (TPU film and the modified TPU (M-TPU film containing 2.0 wt.% inorganic UV absorbers mixture (nano-ZnO/CeO2 with weight ratio of 3 : 2 and 0.5 wt.% organic UV absorbers mixture (UV-531/UV-327 with weight ratio of 1 : 1 were prepared by spin-coating technique. The accelerated aging tests of the films exposed to constant UV radiation of 400 ± 20 µW/cm2 (313 nm with an ozone atmosphere of 100 ± 2 ppm were carried out by using a self-designed aging equipment at ambient temperature and relative humidity of 20%. The aging resistance properties of the films were evaluated by UV-Vis spectra, Fourier transform infrared spectra (FT-IR, photooxidation index, and carbonyl index analysis. The results show that the composite UV absorber has better protection for TPU system, which reduces distinctly the degradation of TPU film. O3/UV aging of the films increases with incremental exposure time. PI and CI of TPU and M-TPU films increase with increasing exposure time, respectively. PI and CI of M-TPU films are much lower than that of TPU film after the same time of exposure, respectively. Distinct synergistic aging effect exists between ozone aging and UV aging when PI and CI are used as evaluation index, respectively. Of course, the formula of these additives needs further improvement for industrial application.

  5. UV Fluorescence Photography of Works of Art : Replacing the Traditional UV Cut Filters with Interference Filters

    Directory of Open Access Journals (Sweden)

    Luís BRAVO PEREIRA

    2010-09-01

    Full Text Available For many years filters like the Kodak Wratten E series, or the equivalent Schneider B+W 415, were used as standard UV cut filters, necessary to obtain good quality on UV Fluorescence photography. The only problem with the use of these filters is that, when they receive the UV radiation that they should remove, they present themselves an internal fluorescence as side effect, that usually reduce contrast and quality on the final image. This article presents the results of our experiences on using some innovative filters, that appeared available on the market in recent years, projected to adsorb UV radiation even more efficiently than with the mentioned above pigment based standard filters: the interference filters for UV rejection (and, usually, for IR rejection too manufactured using interference layers, that present better results than the pigment based filters. The only problem with interference filters type is that they are sensitive to the rays direction and, because of that, they are not adequate to wide-angle lenses. The internal fluorescence for three filters: the B+W 415 UV cut (equivalent to the Kodak Wratten 2E, pigment based, the B+W 486 UV IR cut (an interference type filter, used frequently on digital cameras to remove IR or UV and the Baader UVIR rejection filter (two versions of this interference filter were used had been tested and compared. The final quality of the UV fluorescence images seems to be of a superior quality when compared to the images obtained with classic filters.

  6. Spectral dependence of some UV-B and UV-C responses of Tetrahymena pyriformis irradiated with dye laser generated UV

    International Nuclear Information System (INIS)

    Calkins, John; Colley, Ed; Wheeler, John; Kentucky Univ., Lexington

    1987-01-01

    We have generated UV-B and UV-C radiations using a flashlamp driven tunable dye laser combined with frequency doubling crystals. Using this novel UV source, we have investigated lethality and its modification by growth phase, photoreactivation and caffeine in Tetrahymena pyriformis at 254 nm and from 260-315 nm in 5 nm steps. From the observed responses we have constructed action spectra for lethality, with or without caffeine (a repair inhibitor) and under conditions of photoreactivation. We have also estimated quantum efficiencies for these responses. Our observations suggest that complex changes in response occur at several wavelengths over the UV-C and UV-B regions. (author)

  7. Les instruments de musique dans les pays andins: Equateur, Pérou, Bolivie. Les instruments dans leur contexte historico-géographique [1ère partie

    Directory of Open Access Journals (Sweden)

    1980-01-01

    Full Text Available Cette étude se propose de suivre la création, la transformation et l' utilisation des instruments de musique en relation avec l' histoire andine. Au départ, les premiers Etats de la côte ont un haut degré d'évolution culturelle, que nous avons pu apprécier avec les Mochica, dont les connaissances en matière instrumentale sont indéniables. Les Incas, qui se contentent de diffuser les productions culturelles des sociétés conquises, jouent en quelque sorte le rôle d'organisateurs. Les Espagnols n'ont pas stoppé le processus créateur, mais ils engendrent une société métisse, agent de diffusion des instruments occidentaux. A l'heure actuelle il est donc possible d'identifier dans la majorité des cas l'origine culturelle des instruments, et de déterminer par qui ils sont utilisés. L'emploi d'étalons de mesure, la grande cohérence dans la fabrication des instruments montrent l'ingéniosité des Indiens et l'usage de ces instruments sous forme orchestrale illustre leur grand sens musical. L'étude organologique montre qu'un élément (dans le cas cité, la tarka ne peut être dissocié de l'ensemble duquel il fait partie, et que l'étude des instruments doit tenir compte d'informations parallèles pour aboutir à des conclusions constructives. Este estudio se propone seguir la creación, la transformación y la utilización de los instrumentos de música en relación con la historia andina. Al comienzo, los primeros Estados de la costa tuvieron un alto grado de evolución cultural, que hemos podido apreciar con los Mochica, cuyos conocimientos en materia instrumental son innegables. Los Incas, que se contentan con difundir las producciones culturales de las sociedades conquistadas, representan en cierto modo el papel de organizadores. Los españoles no detuvieron el proceso creador, pero engendraron una sociedad mestiza, agente de difusión de los instrumentos occidentales. Actualmente es pues posible identificar en la mayoría de

  8. UV effects on bottom ice algae

    International Nuclear Information System (INIS)

    Ryan, K.; Buckley, B.

    1993-01-01

    Antarctic sea ice can be surprisingly transparent to UV radiation, particularly during spring when ozone depletion reaches a maximum. A 5% reduction in photosynthetic production was observed in laboratory experiments for UVB levels expected under the ice at this time. In situ studies modifying the UVB radiation falling onto algae were inconclusive. (author). 5 refs

  9. a near ambient pressure UV photoelectron spectroscopy

    Indian Academy of Sciences (India)

    Manoj Kumar Ghosalya

    2018-03-02

    Mar 2, 2018 ... UV photoelectron spectroscopy (NAP-UPS) investigations. MANOJ KUMAR ... gations led to various models of Ag-O2 interaction to explain its role in the .... charge lamp (for He I and He II excitations) are available as photon ...

  10. DNA N-glycosylases and uv repair

    Energy Technology Data Exchange (ETDEWEB)

    Demple, B; Linn, S

    1980-09-18

    Repair of some DNA photoproducts can be mediated by glycosylic bond hydrolysis. Thus, Escherichia coli endonuclease III releases 5,6-hydrated thymines as free bases, while T4 uv endonuclease releases one of two glycosylic bonds holding pyrimidine dimers in DNA. In contrast, uninfected E. coli apparently does not excise pyrimidine dimers via a DNA glycosylase.

  11. A UV-Vis photoacoustic spectrophotometer.

    Science.gov (United States)

    Wiegand, Joseph R; Mathews, L Dalila; Smith, Geoffrey D

    2014-06-17

    A novel photoacoustic spectrophotometer (PAS) for the measurement of gas-phase and aerosol absorption over the UV-visible region of the spectrum is described. Light from a broadband Hg arc lamp is filtered in eight separate bands from 300 to 700 nm using bandpass interference filters (centered at 301 nm, 314 nm, 364 nm, 405 nm, 436 nm, 546 nm, 578 and 687 nm) and modulated with an optical chopper before entering the photoacoustic cell. All wavelength bands feature a 20-s detection limit of better than 3.0 Mm(-1) with the exception of the lower-intensity 687 nm band for which it is 10.2 Mm(-1). Validation measurements of gas-phase acetone and nigrosin aerosol absorption cross sections at several wavelengths demonstrate agreement to within 10% with those measured previously (for acetone) and those predicted by Mie theory (for nigrosin). The PAS instrument is used to measure the UV-visible absorption spectrum of ambient aerosol demonstrating a dramatic increase in the UV region with absorption increasing by 300% from 405 to 301 nm. This type of measurement throughout the UV-visible region and free from artifacts associated with filter-based methods has not been possible previously, and we demonstrate its promise for classifying and quantifying different types of light-absorbing ambient particles.

  12. A Mode Locked UV-FEL

    CERN Document Server

    Parvin, Parviz

    2004-01-01

    An appropriate resonator has been designed to generate femtosecond mode locked pulses in a UV FEL with the modulator performance based on the gain switching. The gain broadening due to electron energy spread affects on the gain parameters, small signal gain (γ0) and saturation intensity (Is), to determine the optimum output coupling as small.

  13. UV Defined Nanoporous Liquid Core Waveguides

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Gopalakrishnan, Nimi; Ndoni, Sokol

    2011-01-01

    Nanoporous liquid core waveguides, where both core and cladding are made from the same material, are presented. The nanoporous polymer used is intrinsically hydrophobic, but selective UV exposure enables it to infiltrate with an aqueous solution, thus raising the refractive index from 1.26 to 1...

  14. Exposure to phenols, parabens and UV filters

    DEFF Research Database (Denmark)

    Joensen, Ulla N.; Jørgensen, Niels; Thyssen, Jacob P.

    2017-01-01

    Concentrations of eight simple phenols, six parabens and nine UV filters were analysed in urine from 65 FLG loss-of-function mutation carriers and 130 non-carriers (controls). Regression analyses, controlling for urinary dilution and confounders, were performed to estimate associations between FLG mutation...

  15. uv keratoconjunctivitis vs. established dose effect relationships

    International Nuclear Information System (INIS)

    Gulvady, N.U.

    1976-01-01

    A patient who received a uv dose to his eyes 11 times greater than the photokeratitic threshold of Pitts and 4 1 / 2 times the photokeratitic threshold as found by Leach. The patient had severe keratoconjunctivitis for 3 days and did not develop any keratitis

  16. Airborne pipeline leak detection: UV or IR?

    Science.gov (United States)

    Babin, François; Gravel, Jean-François; Allard, Martin

    2016-05-01

    This paper presents a study of different approaches to the measurement of the above ground vapor plume created by the spill caused by a small 0.1 l/min (or less) leak in an underground liquid petroleum pipeline. The scenarios are those for the measurement from an airborne platform. The usual approach is that of IR absorption, but in the case of liquid petroleum products, there are drawbacks that will be discussed, especially when using alkanes to detect a leak. The optical measurements studied include UV enhanced Raman lidar, UV fluorescence lidar and IR absorption path integrated lidars. The breadboards used for testing the different approaches will be described along with the set-ups for leak simulation. Although IR absorption would intuitively be the most sensitive, it is shown that UV-Raman could be an alternative. When using the very broad alkane signature in the IR, the varying ground spectral reflectance are a problem. It is also determined that integrated path measurements are preferred, the UV enhanced Raman measurements showing that the vapor plume stays very close to the ground.

  17. UV-LED Curing Efficiency of Wood Coatings

    OpenAIRE

    Véronic Landry; Pierre Blanchet; Gabrielle Boivin; Jean-François Bouffard; Mirela Vlad

    2015-01-01

    Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerf...

  18. Dichotomy in response to indomethacin in uv-C and uv-B induced ultraviolet light inflammation

    International Nuclear Information System (INIS)

    Eaglstein, W.H.; Marsico, A.R.

    1975-01-01

    In subjects irradiated with both UV-C and UV-B ultraviolet light (UVL), 10 μg of intradermal indomethacin decreased the redness in all 13 of the UV-B irradiated areas but in only 2 of 13 of the UV-C irradiated areas. Higher doses of intradermal indomethacin (50 μg and 100 μg) decreased the redness produced by UV-C irradiation in 6 subjects. It is suggested that the failure of 10 μg of indomethacin to decrease the redness of the UV-C induced inflammation, while decreasing the redness in the UV-B induced inflammation, is consistent with the possibility that prostaglandins participate in UV-B but not UV-C induced inflammation

  19. GAT 3 - fuel cells and their management (PACoGES). Progress report; GAT 3 - piles a combustible et leur gestion (PACoGES). Rapport final (juillet 2002 a juin 2004)

    Energy Technology Data Exchange (ETDEWEB)

    Lamy, C.

    2005-07-01

    The Topic Analysis Group PACoGES ('Piles a Combustible et leur Gestion') has conducted thoughts on fuel cells and their management with all the searchers concern with researches and developments on fuel cells and in particular on solid oxide fuel cells (SOFC, ITSOFC) running at high temperature (600 to 1000 C). This has concerned about 200 searchers working in about fifty laboratories (CNRS, CEA, EDF, GDF, INRETS, CNAM, Armines, and several industrial teams). Here is given the final report 2002-2004 concerning all the researches carried out by this Group. (O.M.)

  20. UV-Radiation: From Physics to Impacts

    Directory of Open Access Journals (Sweden)

    Hanns Moshammer

    2017-02-01

    Full Text Available Ultraviolet (UV radiation has affected life at least since the first life forms moved out of the seas and crawled onto the land. Therefore, one might assume that evolution has adapted to natural UV radiation. However, evolution is mostly concerned with the propagation of the genetic code, not with a long, happy, and fulfilling life. Because rickets is bad for a woman giving birth, the beneficial effects of UV-radiation outweigh the adverse effects like aged skin and skin tumors of various grades of malignancy that usually only afflict us at older age. Anthropogenic damage to the stratospheric ozone layer and frighteningly high rates of melanoma skin cancer in the light-skinned descendants of British settlers in Australia piqued interest in the health impacts of UV radiation. A changing cultural perception of the beauty of tanned versus light skin and commercial interests in selling UV-emitting devices such as tanning booths caught public health experts off-guard. Counseling and health communication are extremely difficult when dealing with a “natural” risk factor, especially when this risk factor cannot (and should not be completely avoided. How much is too much for whom or for which skin type? How even measure “much”? Is it the (cumulative dose or the dose rate that matters most? Or should we even construct a more complex metric such as the cumulative dose above a certain dose rate threshold? We find there are still many open questions, and we are glad that this special issue offered us the opportunity to present many interesting aspects of this important topic.

  1. Thermoluminescence sensitivity of ulexite after UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mats@cu.edu.tr [Cukurova University, Arts-Sciences Faculty, Physics Department, 01330 Adana (Turkey); CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, (CSIC), C/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

    2015-04-15

    Highlights: •UV-induced thermoluminescence emission of Turkish ulexite was studied. •There are three groups of components. •The UV exposures were performed at controlled temperatures. -- Abstract: The effects of UV radiation on the thermoluminescence (TL) properties of natural materials, in contrast to synthetic materials, have been scarcely studied. We report on the UV-induced thermoluminescence emission of a Turkish ulexite (NaCaB{sub 5}O{sub 6}(OH){sub 6}·5H{sub 2}O) that displays very complex TL glow curves, with at least three groups of components peaked at 130–140 °C, 240 °C and, 340 °C, wherein the last group is weaker. Such emission could be associated with structural changes in the lattice as well as alkali self-diffusion processes. The UV exposure performed at controlled temperatures (at room temperature (RT), 50 °C and 100 °C) produced a (i) different evolutions of the intensities of each maximum, which are directly related to the controlled thermal treatment; (ii) different intensity ratios among the groups of components; (iii) different activation energies (E{sub a}) (1.13 eV for RT, 0.99 eV for 50 °C and 0.49 eV for 100 °C) calculated using the initial rise method; and (iv) similar scattering values (12.4%, 8.2% and 12.8%), which were not a function of the controlled temperature. The thermal stability tests conducted on this borate at different temperatures, based on the T{sub stop} protocol, confirm the presence of a continuum in the distribution of the trap system with progressively increasing E{sub a} (from 0.60 to 0.90 eV)

  2. Waterborne UV coating for industrial applications

    International Nuclear Information System (INIS)

    Bhattacharya, I.N.

    2007-01-01

    (Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

  3. Row orientation effect on UV-B, UV-A and PAR solar irradiation components in vineyards at Tuscany, Italy

    Science.gov (United States)

    Grifoni, D.; Carreras, G.; Zipoli, G.; Sabatini, F.; Dalla Marta, A.; Orlandini, S.

    2008-11-01

    Besides playing an essential role in plant photosynthesis, solar radiation is also involved in many other important biological processes. In particular, it has been demonstrated that ultraviolet (UV) solar radiation plays a relevant role in grapevines ( Vitis vinifera) in the production of certain important chemical compounds directly responsible for yield and wine quality. Moreover, the exposure to UV-B radiation (280-320 nm) can affect plant-disease interaction by influencing the behaviour of both pathogen and host. The main objective of this research was to characterise the solar radiative regime of a vineyard, in terms of photosynthetically active radiation (PAR) and UV components. In this analysis, solar spectral UV irradiance components, broadband UV (280-400 nm), spectral UV-B and UV-A (320-400 nm), the biological effective UVBE, as well as the PAR (400-700 nm) component, were all considered. The diurnal patterns of these quantities and the UV-B/PAR and UV-B/UV-A ratios were analysed to investigate the effect of row orientation of the vineyard in combination with solar azimuth and elevation angles. The distribution of PAR and UV irradiance at various heights of the vertical sides of the rows was also studied. The results showed that the highest portion of plants received higher levels of daily radiation, especially the UV-B component. Row orientation of the vines had a pronounced effect on the global PAR received by the two sides of the rows and, to a lesser extent, UV-A and UV-B. When only the diffused component was considered, this geometrical effect was greatly attenuated. UV-B/PAR and UV-A/PAR ratios were also affected, with potential consequences on physiological processes. Because of the high diffusive capacity of the UV-B radiation, the UV-B/PAR ratio was significantly lower on the plant portions exposed to full sunlight than on those in the shade.

  4. Transmission of UV-irradiance into nectarine fruit

    International Nuclear Information System (INIS)

    Blanke, M.M.

    1996-01-01

    With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

  5. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    International Nuclear Information System (INIS)

    Kondratiev, Y.S.; Brukhansky, G.V.; Andreeva, I.V.; Skavronskaya, A.G.

    1977-01-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed. (orig.) [de

  6. UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

    International Nuclear Information System (INIS)

    Lochmann, E.R.; Lochmann, G.

    1997-01-01

    The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

  7. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    Energy Technology Data Exchange (ETDEWEB)

    Kondratiev, Y S; Brukhansky, G V; Andreeva, I V; Skavronskaya, A G [Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Ehpidemiologii i Mikrobiologii

    1977-12-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed.

  8. Effect of uvs1, uvs2 and xrs mutations on the radiosensitivity and the induced mitotic recombination frequency in diploid yeast cells

    International Nuclear Information System (INIS)

    Suslova, N.G.; Fedorova, I.V.; Zheleznyakova, N.Yu.

    1975-01-01

    The influence of the loci of radiosensitivity uvs1, uvs2, and xrs in the homozygous state at the diploid level on the sensitivity to UV and ionizing radiation and induced mitotic recombination was studied in the yeast Sacch. cerevisiae. Hypersensitivity to UV irradiation was detected in the diploids uvs2 uvs2 xrs xrs in comparision with the corresponding control. The diploid uvs1 uvs1 uvs2 uvs2 does not differ in UV sensitivity from the diploid uvs1 uvs1 UVS2 UVS2. These facts demonstrate that the uvs1 and uvs2 mutations, on the one hand, and the xrs mutations, on the other, normally control different pathways of elimination of UV-induced damages. It was shown that the diploid uvs2 uvs2 xrs3 xrs3 is far more sensitive to the lethal action of x rays than the control diploid UVS2 UVS2 xrs3 xrs3. Consequently, the mutations uvs2 and xrs3 block different modes of repair of damages induced by ionizing radiation. In all the double-mutant diploids, the frequency of mitotic recombination induced by UV rays increases sharply in comparison with that of the radioresistant diploids UVS UVS XRS XRS and the UV-sensitive diploids uvs2 uvs2 XRS XRS. Possible causes of the observed phenomenon are discussed. It was established that in a diploid homozygous for the loci uvs2 xrs5, the frequency of mitotic recombination induced by x rays increases extremely sharply. This fact confirms the hypothesis that the gene product of the locus uvs2 participates in the repair of DNA after the action of ionizing radiation. (author)

  9. Aluminium-nickel-iron alloys resistant to corrosion by water at high temperature. Their basic properties - their improvement; Les alliages aluminium-nickel-fer resistant a la corrosion par l'eau a haute temperature. Bases de leurs proprietes - leur amelioration

    Energy Technology Data Exchange (ETDEWEB)

    Coriou, H; Fournier, R; Grall, L; Hure, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The development of the investigations carried out on these alloys is reviewed, showing the establishment of their fundamental, particularly structural, properties. This is followed by studies on: 1 - The penetration process in corrosion. The results of micrographic studies of the metal oxide interface are given for a series of alloys treated in water and steam between 350 and 395 deg. C. The hypothesis of attack by pockets of gas pressure is corroborated, and a second process of deep penetration by islands of intergranular-type corrosion is shown to take place. These patches, distinct from the surface corrosion layer and sometimes forming at a considerable depth inside the metal, would be due to heterogeneities in composition of the solid solution making up the matrix of these alloys. 2 - The role of titanium and zirconium additions on rolled metal. Systematic studies are carried out on a series of alloys with titanium and zirconium contents between 0.05 and 0.15 per cent. The favourable effect of titanium in particular has been demonstrated. Zirconium acts in the same way, but less efficiently. The improvement due to these additions can be compared to their action on the distribution of the second phases, which tend to become more pronounced and more homogeneously distributed. The influence of solder on these alloys has been studied, showing up the part played by the structure gradients introduced by fission. (author) [French] Apres un rappel de l'evolution des etudes sur ces alliages, montrant l'etablissement de leurs proprietes fondamentales et, en particulier, structurales, on etudie: 1 - Les processus de penetration de la corrosion. On expose les resultats de l'etude micrographique de l'interface metal-oxyde sur une serie d'alliages traites dans l'eau et la vapeur entre 350 et 395 deg. C. On verifie l'hypothese de l'attaque par poches de pression gazeuse et on met en evidence un second processus de progression en profondeur par ilots de corrosion de type

  10. Photodegradation of sulfasalazine and its human metabolites in water by UV and UV/peroxydisulfate processes.

    Science.gov (United States)

    Ji, Yuefei; Yang, Yan; Zhou, Lei; Wang, Lu; Lu, Junhe; Ferronato, Corinne; Chovelon, Jean-Marc

    2018-04-15

    The widespread occurrence of pharmaceuticals and their metabolites in natural waters has raised great concerns about their potential risks on human health and ecological systems. This study systematically investigates the degradation of sulfasalazine (SSZ) and its two human metabolites, sulfapyridine (SPD) and 5-aminosalicylic acid (5-ASA), by UV and UV/peroxydisulfate (UV/PDS) processes. Experimental results show that SPD and 5-ASA were readily degraded upon UV 254 nm direct photolysis, with quantum yields measured to be (8.6 ± 0.8) × 10 -3 and (2.4 ± 0.1) × 10 -2  mol Einstein -1 , respectively. Although SSZ was resistant to direct UV photolysis, it could be effectively removed by both UV/H 2 O 2 and UV/PDS processes, with fluence-based pseudo-first-order rate constants determined to be 0.0030 and 0.0038 cm 2  mJ -1 , respectively. Second-order rate constant between SO 4 •- and SSZ was measured as (1.33 ± 0.01) × 10 9  M -1 s -1 by competition kinetic method. A kinetic model was established for predicting the degradation rate of SSZ in the UV/PDS process. Increasing the dosage of PDS significantly enhanced the degradation of SSZ in the UV/PDS process, which can be well predicted by the developed kinetic model. Natural water constituents, such as natural organic matter (NOM) and bicarbonate (HCO 3 - ), influenced the degradation of SSZ differently. The azo functional group of SSZ molecule was predicted as the reactive site susceptible to electrophilic attack by SO 4 •- by frontier electron densities (FEDs) calculations. Four intermediate products arising from azo bond cleavage and SO 2 extrusion were identified by solid phase extraction-liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-MS/MS). Based on the products identified, detailed transformation pathways for SSZ degradation in the UV/PDS system were proposed. Results reveal that UV/PDS could be an efficient approach for remediation of water

  11. You, me and UV under the sun in South Africa

    CSIR Research Space (South Africa)

    Wright, C

    2009-01-01

    Full Text Available This article asks just how harmful are our solar UV rays? It explains what previous researches tell us about how much UV radiation our children are likely to receive and what are the health risks....

  12. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina-Maria; van Geffen, Jos H. G. M.; Taylor, Michael; Fountoulakis, Ilias; Koukouli, Maria-Elissavet; van Weele, Michiel; van der A, Ronald J.; Bais, Alkiviadis; Meleti, Charikleia; Balis, Dimitrios

    2017-06-01

    This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS

  13. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    M.-M. Zempila

    2017-06-01

    Full Text Available This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4 UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh, in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990 and with a very low bias (0.000 to 0.011 in absolute units proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5

  14. Comparative investigation of X-ray contrast medium degradation by UV/chlorine and UV/H2O2.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Pang, Suyan

    2018-02-01

    The degradation of iopamidol and diatrizoate sodium (DTZ) by UV/chlorine was carried out according to efficiency, mechanism, and oxidation products, and compared to that by UV/H 2 O 2 . The pseudo-first order rate (k') of iopamidol and DTZ was accelerated by UV/chlorine compared to that by UV and chlorine alone. k' of iopamidol and DTZ by UV/chlorine increased with increasing chlorine dosage. Both of iopamidol and DTZ could not be effectively removed by UV/H 2 O 2 compared to that by UV/chlorine. Secondary radicals (Cl 2 - and ClO) rather than primary radicals (HO and Cl) were demonstrated to be mainly responsible for the enhanced removal of iopamidol and DTZ by UV/chlorine. The oxidation products of iopamidol and DTZ resulting from UV/chlorine and UV/H 2 O 2 process were identified, and differences existed in the two systems. IO 3 - (the desired sink of I - ) was the major inorganic product in the UV/chlorine process whereas I - was the predominant inorganic product in the UV/H 2 O 2 process. The formation of chlorine-containing products during the degradation of iopamidol and DTZ by UV/chlorine was also observed. H-abstraction, additions, de-iodination were shared during the degradation of iopamidol by UV/chlorine and UV/H 2 O 2 . Neutral pH condition was preferred for the removal of iopamidol and DTZ by UV/chlorine. UV/chlorine could also be applied in real waters for the removal of iopamidol and DTZ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Prediction of UV spectra and UV-radiation damage in actual plasma etching processes using on-wafer monitoring technique

    International Nuclear Information System (INIS)

    Jinnai, Butsurin; Fukuda, Seiichi; Ohtake, Hiroto; Samukawa, Seiji

    2010-01-01

    UV radiation during plasma processing affects the surface of materials. Nevertheless, the interaction of UV photons with surface is not clearly understood because of the difficulty in monitoring photons during plasma processing. For this purpose, we have previously proposed an on-wafer monitoring technique for UV photons. For this study, using the combination of this on-wafer monitoring technique and a neural network, we established a relationship between the data obtained from the on-wafer monitoring technique and UV spectra. Also, we obtained absolute intensities of UV radiation by calibrating arbitrary units of UV intensity with a 126 nm excimer lamp. As a result, UV spectra and their absolute intensities could be predicted with the on-wafer monitoring. Furthermore, we developed a prediction system with the on-wafer monitoring technique to simulate UV-radiation damage in dielectric films during plasma etching. UV-induced damage in SiOC films was predicted in this study. Our prediction results of damage in SiOC films shows that UV spectra and their absolute intensities are the key cause of damage in SiOC films. In addition, UV-radiation damage in SiOC films strongly depends on the geometry of the etching structure. The on-wafer monitoring technique should be useful in understanding the interaction of UV radiation with surface and in optimizing plasma processing by controlling UV radiation.

  16. The global and UV-B radiation over Egypt

    OpenAIRE

    BASSET, H. A.; KORANY, M. H.

    2007-01-01

    This work studies the relation between UV-B radiation and global radiation over Egypt. The relationships between the global solar radiation and UV-B radiation at four stations in Egypt have been studied, and linear empirical formulas for estimating UV-B from global radiation at these stations has been deduced. The deduced equations were applied to calculate the UV-B radiation for other stations where measurements were unavailable, using records of global radiation at these stations. Because o...

  17. Migration et développement : les politiques de la Chine et de l’Inde à l’égard de leurs communautés d’outre-mer

    Directory of Open Access Journals (Sweden)

    Jérôme Elie

    2011-05-01

    Full Text Available En se basant sur les cas de l’Inde et de la Chine, deux pays à forte émigration qui ont élaboré des politiques visant à favoriser les liens avec leurs ressortissants vivant à l’étranger, cet article propose une contribution au débat académique et politique sur les relations qui existent entre le phénomène migratoire et le développement des pays d’origine. En prenant comme exemple les mesures que ces deux pays ont échafaudées en faveur de leurs communautés outre-mer, il est possible de relever la nécessité de créer une ou des structures institutionnelles promouvant les initiatives individuelles. Une telle démarche permet également de souligner l’importance de la dimension réciproque qui ne doit pas manquer de s’instaurer entre le gouvernement du pays d’origine et les migrants.

  18. Improving UV Resistance of High Performance Fibers

    Science.gov (United States)

    Hassanin, Ahmed

    High performance fibers are characterized by their superior properties compared to the traditional textile fibers. High strength fibers have high modules, high strength to weight ratio, high chemical resistance, and usually high temperature resistance. It is used in application where superior properties are needed such as bulletproof vests, ropes and cables, cut resistant products, load tendons for giant scientific balloons, fishing rods, tennis racket strings, parachute cords, adhesives and sealants, protective apparel and tire cords. Unfortunately, Ultraviolet (UV) radiation causes serious degradation to the most of high performance fibers. UV lights, either natural or artificial, cause organic compounds to decompose and degrade, because the energy of the photons of UV light is high enough to break chemical bonds causing chain scission. This work is aiming at achieving maximum protection of high performance fibers using sheathing approaches. The sheaths proposed are of lightweight to maintain the advantage of the high performance fiber that is the high strength to weight ratio. This study involves developing three different types of sheathing. The product of interest that need be protected from UV is braid from PBO. First approach is extruding a sheath from Low Density Polyethylene (LDPE) loaded with different rutile TiO2 % nanoparticles around the braid from the PBO. The results of this approach showed that LDPE sheath loaded with 10% TiO2 by weight achieved the highest protection compare to 0% and 5% TiO2. The protection here is judged by strength loss of PBO. This trend noticed in different weathering environments, where the sheathed samples were exposed to UV-VIS radiations in different weatheromter equipments as well as exposure to high altitude environment using NASA BRDL balloon. The second approach is focusing in developing a protective porous membrane from polyurethane loaded with rutile TiO2 nanoparticles. Membrane from polyurethane loaded with 4

  19. UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

    Directory of Open Access Journals (Sweden)

    Alyaa M. Zyara

    2017-01-01

    Full Text Available UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV- and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93–2.73 Log10-reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log10-reductions to 4.30–5.16. Traditional mercury UV (Hg-UV lamp at a 254 nm wavelength caused 0.67–4.08 Log10-reductions in 2 min and 4.56–7.21 Log10-reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log10-reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV- and/or Cl-resistant viruses.

  20. Increased resistance of environmental anaerobic spores to inactivation by UV

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

    2004-01-01

    Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV.

  1. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  2. People with Increased Risk of Eye Damage from UV Light

    Science.gov (United States)

    ... With Increased Risk of Eye Damage from UV Light Leer en Español: Algunas Personas Están en Mayor Riesgo de Sufrir Daño Ocular por los Rayos UV Written By: Shirley Dang Apr. 30, 2014 Everyone of any age and any degree of skin pigmentation is susceptible to UV damage. Children are ...

  3. Reactivation of UV- and γ-irradiated herpes virus in UV- and X-irradiated CV-1 cells

    International Nuclear Information System (INIS)

    Takimoto, K.; Niwa, O.; Sugahara, T.

    1982-01-01

    Enhanced reactivation of UV- and γ-irradiated herpes virus was investigated by the plaque assay on CV-1 monkey kidney monolayer cells irradiated with UV light or X-rays. Both UV- and X-irradiated CV-1 cells showed enhancement of survival of UV-irradiated virus, while little or no enhancement was detected for γ-irradiated virus assayed on UV- or X-irradiated cells. The enhanced reactivation of UV-irradiated virus was greater when virus infection was delayed 24 or 48 h, than for infection immediately following the irradiation of cells. Thus the UV- or X-irradiated CV-1 cells are able to enhance the repair of UV damaged herpes virus DNA, but not of γ-ray damaged ones. (author)

  4. UV Spectroscopy of Metallic Asteroid (16) Psyche

    Science.gov (United States)

    Cunningham, N. J.; Becker, T. M.; Retherford, K. D.; Roth, L.; Feaga, L. M.; Wahlund, J.-E.; Elkins-Tanton, L. T.

    2017-09-01

    Asteroid (16) Psyche is the largest M-type asteroid, and the planned destination of the NASA Discovery mission Psyche and the proposed ESA M5 mission Heavy Metal. Psyche is considered to be the exposed core of a differentiated asteroid, whose mantle has been stripped by collisions; but other histories have been proposed. We observed Psyche with the Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, to obtain a full ultraviolet (UV) spectrum of both of Psyche's hemispheres. We seek to test three possible scenarios for Psyche's origin: Is Psyche the exposed core of a differentiated asteroid? Is it an asteroid with high olivine content that has been space-weathered? Or did Psyche accrete as-is in a highly-reducing environment early in the history of the solar system? We will present the UV spectra and their implications for Psyche's history.

  5. Immunogenicity of UV-inactivated measles virus

    International Nuclear Information System (INIS)

    Zahorska, R.; Mazur, N.; Korbecki, M.

    1978-01-01

    By means of the antigen extinction limit test it was shown that a triple dose vaccination of guinea pigs with UV-inactivated measles virus gave better results, than a single dose vaccination which was proved by the very low immunogenicity index. For both vaccination schemes (single and triple) the immune response was only sligthly influenced by a change of dose from 10 5 to 10 6 HadU 50 /ml or by the addition of aluminum adjuvant. In the antigen extinction limit test the antibody levels were determined by two methods (HIT and NT) the results of which were statistically equivalent. The UV-inactivated measles virus was also found to induce hemolysis-inhibiting antibodies. (orig.) [de

  6. Effect of UV-irradiation on rotavirus

    International Nuclear Information System (INIS)

    Smirnov, Y.A.; Kapitulets, S.P.; Kaverin, N.V.; Amitina, N.N.; Ginevskaya, V.A.

    1991-01-01

    The effect of UV-irradiation on the infectivity of the SAll rotavirus was examined. The time behavior of the inactivation of infectivity generally exhibited the one-hit pattern. The effect was studied with respect to two phenomena, viz. the RNA-protein linkage and the formation of uracil dimers. To determine the number of the latter, purified 3 H-uridine-labelled rotavirus was exposed to UV radiation, and the RNA was extracted and analyzed by paper chromatography in the ascending mode. The formation of photodimers was found to be an important mechanism in the rotavirus inactivation on conventional irradiation, whereas RNA-protein linkages were observed on the application of high doses only. (author). 3 figs., 10 refs

  7. UV inactivation of pathogenic and indicator microorganisms

    International Nuclear Information System (INIS)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-01-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts

  8. UV inactivation of pathogenic and indicator microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-06-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.

  9. The optimal UV exposure time for vitamin D3 synthesis and erythema estimated by UV observations in Korea

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2016-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) from spectral UV measurements during 2006-2010. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied to the broadband UV measured by UV-Biometer at 6 sites in Korea Thus, the optimal UV exposure time for vitamin D3 synthesis and erythema was estimated for diurnal, seasonal, and annual scales over Korea. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice

  10. UV radiation and its effects. Proceedings

    International Nuclear Information System (INIS)

    1993-01-01

    The National Science Strategy Committee for Climate Change was established in 1991 by the New Zealand Minister of Research, Science and Technology. It advises government through the Minister on research priorities and on levels of expenditure appropriate in various topics relating to climate change. An additional role is to promote coordination between research groups and the user communities to ensure an appropriate range of research strategies. To assist with implementing the latter aspects the NSS Committee will organise workshops on specific aspects of atmosphere and climate change, with a broad spectrum of participants. The first of these was the Workshop on UV Radiation and its Effects held in Christchurch on 20-21 May 1993. The workshop had 40 participants, including representatives from specialist science groups, medicine, veterinary science, farming, forestry and environmental groups. This publication will update the interested reader, whether scientist or lay-person, on the current state of knowledge on changing UV radiation levels and potential problems. As the summaries of papers show, research on ozone levels and on UV radiation and its effects is particularly appropriate for New Zealand scientists with their access to sites covering a wide range of latitudes from Antarctica to the Pacific Islands. New Zealand is part of an important international monitoring network, measuring local stratospheric ozone levels and related surface UV radiation levels. There are concerns about increasing UVB levels and the consequent effects on human health, plant and tree growth, and phytoplankton growth in the oceans. Priorities for further work on these areas are included in the summary of the workshop. (author). 13 figs.; 5 tabs

  11. Cycloaliphatic epoxide resins for cationic UV - cure

    International Nuclear Information System (INIS)

    Verschueren, K.; Balwant Kaur

    1999-01-01

    This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

  12. Mechanisms underlying UV-induced immune suppression

    International Nuclear Information System (INIS)

    Ullrich, Stephen E.

    2005-01-01

    Skin cancer is the most prevalent form of human neoplasia. Estimates suggest that in excess of one million new cases of skin cancer will be diagnosed this year alone in the United States (www.cancer.org/statistics). Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer. The cost of treating non-melanoma skin cancer is estimated to be in excess of US$ 650 million a year [J.G. Chen, A.B. Fleischer, E.D. Smith, C. Kancler, N.D. Goldman, P.M. Williford, S.R. Feldman, Cost of non-melanoma skin cancer treatment in the United States, Dermatol. Surg. 27 (2001) 1035-1038], and when melanoma is included, the estimated cost of treating skin cancer in the United States is estimated to rise to US$ 2.9 billion annually (www.cancer.org/statistics). Because the morbidity and mortality associated with skin cancer is a major public health problem, it is important to understand the mechanisms underlying skin cancer development. The primary cause of skin cancer is the ultraviolet (UV) radiation found in sunlight. In addition to its carcinogenic potential, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. The focus of this manuscript will be to review the mechanisms underlying the induction of immune suppression following UV exposure. Particular attention will be directed to the role of soluble mediators in activating immune suppression

  13. Key factors for UV curable pigment dispersions

    International Nuclear Information System (INIS)

    Magny, B.; Pezron, E.; Ciceron, P.H.; Askienazy, A.

    1999-01-01

    UV oligomers with good pigment dispersion are needed to allow good formulation flexibility and possibility to apply thinner films. Pigment dispersion mainly depends on three phenomena: the wetting of agglomerates, the breakage of agglomerates by mechanical stress and the stabilization of smaller agglomerates and primary particles against flocculation. It has been shown that oligomers with low viscosity and low surface tension induce a good pigment wetting. Examples of monomers and oligomers for good pigment dispersion are given

  14. UV induced thermoluminescence in rare earth oxide doped phosphors: possible use for UV dosimetry

    International Nuclear Information System (INIS)

    Yeh, S.-M.; Su, C.-S.

    1996-01-01

    UV induced thermoluminescent (TL) phenomena in some phosphors doped with rare earth oxides (Gd 2 O 3 :Eu, Gd 2 O 3 :Tb, Gd 2 O 3 :Dy and Y 2 O 3 :EU) have been investigated. Gd 2 O 3 :Eu and Y 2 O 3 :Eu have been found to possess prominent TL phenomena. A stable high temperature glow peak has been found at 345 o C in the cubic (C type) crystalline structure of Gd 2 O 3 :Eu. A more stable high temperature glow peak has also been found at about 380 o C in Y 2 O 3 :Eu. The sensitivity is high enough to be used as UV sensors. TL phenomena in Gd 2 O 3 :Tb and Gd 2 O 3 :Dy have also been investigated, but their TL intensities are much weaker than that of Gd 2 O 3 :Eu or Y 2 O 3 :Eu. On the other hand, all glow peaks of Gd 2 O 3 :Tb and Gd 2 O 3 :Dy are unstable at room temperature, therefore, Gd 2 O 3 :Tb and Gd 2 O 3 :Dy are not suitable for use as UV detectors. According to the above properties, the C type (cubic) crystalline structure of the Gd 2 O 3 :Eu phosphor seems to possess the potential of being the TL material for UV measurement. The position of the high temperature glow peak depends on the total UV exposure. It locates at about 380 o C when this phosphor was irradiated by 302 nm UV at 2.4 mJ.cm -2 exposure, but it shifts to 345 o C at 19.2 mJ.cm -2 or higher exposure. The response curves of this phosphor for various wavelengths, e.g. 253.7 nm, 302 nm, and 365 nm, were also measured. This phosphor is sensitive enough to measure background UV radiations, such as sunlight, bulb light etc. (author)

  15. UV-blocking spectacle lens protects against UV-induced decline of visual performance.

    Science.gov (United States)

    Liou, Jyh-Cheng; Teng, Mei-Ching; Tsai, Yun-Shan; Lin, En-Chieh; Chen, Bo-Yie

    2015-01-01

    Excessive exposure to sunlight may be a risk factor for ocular diseases and reduced visual performance. This study was designed to examine the ability of an ultraviolet (UV)-blocking spectacle lens to prevent visual acuity decline and ocular surface disorders in a mouse model of UVB-induced photokeratitis. Mice were divided into 4 groups (10 mice per group): (1) a blank control group (no exposure to UV radiation), (2) a UVB/no lens group (mice exposed to UVB rays, but without lens protection), (3) a UVB/UV400 group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [UV400 coating]), and (4) a UVB/photochromic group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [photochromic coating]). We investigated UVB-induced changes in visual acuity and in corneal smoothness, opacity, and lissamine green staining. We also evaluated the correlation between visual acuity decline and changes to the corneal surface parameters. Tissue sections were prepared and stained immunohistochemically to evaluate the structural integrity of the cornea and conjunctiva. In blank controls, the cornea remained undamaged, whereas in UVB-exposed mice, the corneal surface was disrupted; this disruption significantly correlated with a concomitant decline in visual acuity. Both the UVB/UV400 and UVB/photochromic groups had sharper visual acuity and a healthier corneal surface than the UVB/no lens group. Eyes in both protected groups also showed better corneal and conjunctival structural integrity than unprotected eyes. Furthermore, there were fewer apoptotic cells and less polymorphonuclear leukocyte infiltration in corneas protected by the spectacle lenses. The model established herein reliably determines the protective effect of UV-blocking ophthalmic biomaterials, because the in vivo protection against UV-induced ocular damage and visual acuity decline was easily defined.

  16. coating layers under the UV loading

    Directory of Open Access Journals (Sweden)

    Kulhavý Petr

    2017-01-01

    Full Text Available For individual components as well as for the final products is need to determine their resistance and other mechanical properties, which can be changing due to the various conditions and simultaneously we try to get still closer to the real operating conditions.Currently, given the need to guarantee a perfect quality of the product throughout its entire life cycle, it is necessary to assess the protective layers that are in direct contact with the material itself or with the future products.This article presents the results of testing individual components of the selected materials and their resistance to the UV rays. These were some samples of a prelacquered sheet and a powder coated plate after their forming, next by pigment colored concrete cubes, artificial wood and a prototype sample of the translucent material Licrete. Compared to a conventional climate tests such as heat, cold, humidity or the salt chambers, the colored protection layers were subjected to a strong UV rays. Subsequently was evaluated the change of the colors, brightness and where it was possible also the adhesion parameters and thickness of the coated layer. The measurement wasn’t focused only on the adhesion and color stability, but also to a violation of microstructure due to high temperatures caused by the UV ray. The selected specimens were tested in a device which simulates solar radiation and then were them evaluated the changes of a colors and on the surface structure.

  17. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

    Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

  18. UV dissociation of vibrationally excited UF6

    International Nuclear Information System (INIS)

    Alexandre, M.; Clerc, M.; Gagnon, R.; Gilbert, M.; Isnard, P.; Nectoux, P.; Rigny, P.; Weulersse, J.M.

    1983-01-01

    Before application of laser photodissociation of UF 6 to the separation of uranium isotopes becomes practical, isotopic selectivity should be optimized. We present here results on the cross sections involved in the irradiation of UF 6 simultaneously with infrared and ultraviolet lasers, as a function of wavelengths, fluence and temperature (at 293 K and 105 K, in an adiabatic expansion). The experiment uses a Nd 3+ YAG pumped lithium niobate optical parametric oscillator as a tunable 16 μ light source. Energies of the order of 1 mJ can be obtained with linewidths smaller than 0.1 cm - . The UV source used is based on ND 3+ YAG pumped dye laser and various frequency mixing schemes. At low temperature the frequency variation of the absorbed infrared energy per molecule depends markedly on the IR fluence phisub(IR) with a maximum value varying as phisub(IR)sup(-1/2) and a frequency extension far beyond the low level absorption spectrum. The absorbed vibrational energy leads to a change in the UV cross section comparable with the effect of a rise in temperature. Using this a model is put forward to express the isotopic selectivity 235 U/ 238 U as a function of UV wavelength and IR irradiation conditions. Experimental results agree with this model, and yield to maximum selectivity close to two [fr

  19. Omega: A 24-beam UV irradiation facility

    International Nuclear Information System (INIS)

    Richardson, M.C.; Beich, W.; Delettrez, J.

    1985-01-01

    The authors report on the characterization and performance of the 24-beam Omega laser facility under full third harmonic (351-nm) upconversion. This system provides for the first time a multibeam laser facility for the illumination of spherical targets with UV laser light in symmetric irradiation conditions with energies in the kilojoule range. This facility is capable of providing sufficient irradiation uniformity to test concepts of direct drive laser fusion with UV-driven ablation targets. The results of initial studies of ablatively driven DT-fueled glass microballoon targets will be described. The 24-beam Omega Nd:phosphate glass facility is capable of providing at 1054 nm output powers in excess of 10 TW in short ( 10 4 full system shots to date) irradiation facility with beam synchronism of approx. =3 psec, beam placement accuracy on target of 10 μm, and interbeam energy variance of approx. =2%. From measured target plane intensity distributions, overall illumination uniformity with tangentially focused beams is estimated to be approx. =5%. In 1984, a symmetric set of six beams was upconverted to 351-nm radiation using the polarization-mismatch scheme developed by Craxton. Monolithic cells of 20-cm clear aperture containing both frequency and doubler and tripler type II KDP crystals in index-matching propylene carbonate liquid were incorporated to output of six of the Omega beams with a full set of UV beam diagnostics

  20. Application of UV Imaging in Formulation Development.

    Science.gov (United States)

    Sun, Yu; Østergaard, Jesper

    2017-05-01

    Efficient drug delivery is dependent on the drug substance dissolving in the body fluids, being released from dosage forms and transported to the site of action. A fundamental understanding of the interplay between the physicochemical properties of the active compound and pharmaceutical excipients defining formulation behavior after exposure to the aqueous environments and pharmaceutical performance is critical in pharmaceutical development, manufacturing and quality control of drugs. UV imaging has been explored as a tool for qualitative and quantitative characterization of drug dissolution and release with the characteristic feature of providing real-time visualization of the solution phase drug transport in the vicinity of the formulation. Events occurring during drug dissolution and release, such as polymer swelling, drug precipitation/recrystallization, or solvent-mediated phase transitions related to the structural properties of the drug substance or formulation can be monitored. UV imaging is a non-intrusive and simple-to-operate analytical technique which holds potential for providing a mechanistic foundation for formulation development. This review aims to cover applications of UV imaging in the early and late phase pharmaceutical development with a special focus on the relation between structural properties and performance. Potential areas of future advancement and application are also discussed.

  1. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Chevremont, A.-C., E-mail: anne-celine.chevremont@imbe.fr [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France); Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Farnet, A.-M. [Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Coulomb, B.; Boudenne, J.-L. [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France)

    2012-06-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO{sub 2}. - Highlights: Black-Right-Pointing-Pointer We test UV-LEDs as an urban wastewater tertiary treatment. Black-Right-Pointing-Pointer UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. Black-Right-Pointing-Pointer Coupled wavelengths have the most efficient bactericidal effect. Black-Right-Pointing-Pointer Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  2. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    International Nuclear Information System (INIS)

    Chevremont, A.-C.; Farnet, A.-M.; Coulomb, B.; Boudenne, J.-L.

    2012-01-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2 . - Highlights: ► We test UV-LEDs as an urban wastewater tertiary treatment. ► UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. ► Coupled wavelengths have the most efficient bactericidal effect. ► Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  3. Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device.

    Science.gov (United States)

    Boyce, John M; Farrel, Patricia A; Towle, Dana; Fekieta, Renee; Aniskiewicz, Michael

    2016-06-01

    OBJECTIVE To evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device. DESIGN Prospective observational study. METHODS We used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (µWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA. RESULTS Mean UV-C irradiance was nearly 1.0E-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P4 to 1-3 for MRSA, >4 to 1-2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles. CONCLUSION UV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device. Infect Control Hosp Epidemiol 2016;37:667-672.

  4. UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

    Science.gov (United States)

    Han, D.; Xia, Y.; Yokota, S.; Kim, J. W.

    2017-12-01

    This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µm are experimentally investigated. In the case of 500 µm KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µm were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm-3) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm-3) fabricated by front UV. This paper proves that the proposed

  5. UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

    International Nuclear Information System (INIS)

    Han, D; Xia, Y; Yokota, S; Kim, J W

    2017-01-01

    This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µ m are experimentally investigated. In the case of 500 µ m KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µ m were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm −3 ) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm −3 ) fabricated by front UV. This paper proves that the

  6. UV-induced N2O emission from plants

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2014-01-01

    investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

  7. UV-observations with a Brewer spectrophotometer at Hohenpeissenberg

    Science.gov (United States)

    Vandersee, Winfried; Koehler, U.

    1994-01-01

    Regular spectral UV-B measurements with a Brewer spectrophotometer have been performed at Hohenpeissenberg since 1990. Intercomparison of the Brewer instrument with other UV-B monitoring devices have shown agreement to within plus or minus 10 percent. Comparisons of UV-B spectra measured on fair weather days reveal the well known increasing influence of ozone on UV-B irradiance with decreasing wavelengths. The integral amplification factor the erythemal irradiance reaches values up to 2.8, which can be diminished by increasing turbidity. The influence of cirrus cloud on the UV-B is also shown.

  8. UV-irradiation effects on polyester nuclear track detector

    International Nuclear Information System (INIS)

    Agarwal, Chhavi; Kalsi, P.C.

    2010-01-01

    The effects of UV irradiation (λ=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the absorption edge due to UV irradiation was seen in the UV-visible spectra. FTIR studies also indicate the scission of the chemical bonds, thereby further validating the bulk-etch rate results.

  9. UV dose-effect relationships and current protection exposure standards

    International Nuclear Information System (INIS)

    Singh, M.S.; Campbell, G.W.

    1982-04-01

    In this paper we have attempted to quantify the health effects in man of uv-radiation exposure of wavelengths from 240 nm to 320 nm. Exposure to uv in this region could result in the formation of skin cancer or premature aging in man. The induction of cancer by uv radiation results from changes in genetic material. We have used the DNA action spectrum coupled with the uv skin cancer data available in the literature to derive the dose-effect relationships. The results are compared against the current uv protection standards

  10. Effect of UV on DNA synthesis in UV-resistant insect cells

    International Nuclear Information System (INIS)

    Styer, S.C.; Meechan, P.J.; Griffiths, T.D.

    1987-01-01

    Insect cells are most resistant to killing by 254 nm ultraviolet light (UV) than mammalian cells. Because they have an active photolyase, it may be possible to generate a higher number of [6-4] PyC lesions per genome, allowing the possibility to distinguish between the effects of [5-6] pyrimidine lesions and the nonphotoreactable [6-4] lesions on DNA replication. IAL-PID2 cells, derived from imaginal wing discs of the Indian meal moth were exposed to UV followed by photoreactivating light (PR) or sham treatment and then analyzed by measuring the incorporation of [/sup 3/H]-thymidine into acid precipitable form. As expected, there was a fluence-dependent decrease in the amount of thymidine incorporated after exposure to UV. The response was similar to that observed in wild type CHO cells (AAS) except that the rate of decline was more rapid. When PR followed UV, there was less of a decline in thymidine incorporation and a more rapid recovery. However, thymidine incorporation did not return to control levels as rapidly as expected if [5-6] lesions were the only lesions involved in the disruption of DNA synthesis after exposure to UV

  11. Development of a low cost UV index datalogger and comparison between UV index sensors

    Science.gov (United States)

    Gomes, L. M.; Ventura, L.

    2018-02-01

    Ultraviolet radiation (UVR) is the part of radiation emitted by the Sun, with range between 280 nm and 400 nm, and that reaches the Earth's surface. The UV rays are essential to the human because it stimulates the production of vitamin D but this radiation may be related to several health problems, including skin cancer and ocular diseases like pterygium, photokeratitis, cataract and more. To inform people about UV radiation, it is adopted the Ultraviolet Index (UVI). This UVI consists in a measure of solar UV radiation level, which contributes to cause sunburn on skin, also known as Erythema, and is indicated as an integer number between 1 and 14, associated to categories from low to extreme respectively. The aim of this work was to develop a low cost UVI datalogger capable of measuring three different UVI sensors simultaneously, record their data with timestamp and serve the measures online through a dedicated server, so general public can access their data and see the current UV radiation conditions. We also compared three different UVI sensors (SGlux UV cosine, Skye SKU440 and SiLabs SI1145) between them and with meteorological models during a period of months to verify their compliance. With five months data, we could verify the sensors working characteristics and decide which among them are the most suitable for research purposes.

  12. Photostability of cosmetic UV filters on mammalian skin under UV exposure.

    Science.gov (United States)

    Stiefel, Constanze; Schwack, Wolfgang; Nguyen, Yen-Thi Hai

    2015-01-01

    Previous studies showed that the common UV filter substances benzophenone-3 (BP-3), butyl methoxydibenzoylmethane (BM-DBM), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (EHS) and ethylhexyl triazone (EHT) were able to react with amino side chains of different proteins in vitro. To transfer the results to mammalian skin conditions, sunscreen products were applied on both prepared fresh porcine skin and glass plates, followed by UV irradiation and the determination of depletion of the respective UV filters. Significantly lower recoveries of the UV filters extracted from skin samples than from glass plates indicated the additional reaction of the UV filters with skin constituents, when proteins will be the most important reactants. Among the products tested, BP-3 showed the greatest differences in recoveries between glass and skin samples of about 13% and 24% after 2 and 4 h of irradiation, respectively, followed by EHS > BM-DBM > OCR > EHMC > EHT. The obtained results raise the question, whether the common in vitro evaluations of sunscreens, using inert substrate materials like roughened quartz or polymethyl methacrylate (PMMA) plates are really suitable to fully replace in vivo methods, as they cannot include skin-typical reactions. © 2014 The American Society of Photobiology.

  13. UV-MAOR - UV-B-specific reactions of marine planktons. Final report

    International Nuclear Information System (INIS)

    Gerbersdorf, S.; Steeger, H.U.; Schubert, H.; Paul, R.J.

    2001-02-01

    An initial finding of the studies performed here is that under certain hydrogeographic and meteorological conditions vertical migration of phyto and zooplankton also occurs in near-shore parts of flat waters. The vertical migration of phytoplankton was induced by exceeding the threshold intensity of approx. 300 μmol photons m -2 s -1 (PAR). However, the sigmoidal course of the reaction of phytoplankton suggests that it is apparently not the PAR intensity alone but the ratio of PAR/UV-B which governs the downward migration. However, the present body of data is not sufficient for a definitive statistical verification of this finding. Light irradiation resulted in an increased density and thus in a reduced buoyancy of flounder spawn. This effect was primarily dependent on intensity and did not increase upon irradiation with UV-B, UV-A and PAR as compared to UV-A and PAR alone. Irradiation with UV-B did not influence the substance located in the vitellus whose absorption maximum was found to be 300 nm, probably gadusol

  14. Damage to UV-sensitive cells by short UV in photographic flashes

    International Nuclear Information System (INIS)

    Menezes, S.; Monteiro, C.

    1996-01-01

    Light emitted by electronic photographic flash units is shown to damage bacteria and human skin fibroblasts deficient in repair systems, with survival curves very similar to those produced by 254 nm short UV. The lesions induced by these flashes are as photorepairable by the photolyase enzyme as those induced by 254 nm UV and result in equivalent survival rates. Biological dosimetry performed with microorganisms highly sensitive to UV (Escherichia coli K12 AB2480, deficient in excision and recombinational-dependent repair systems and Bacillus subtilis UVSSP spores, deficient in excision and in a specific spore repair process) revealed that each 1 ms flash of light from the photographic unit used in this work contained the equivalent of 0.25 J m -2 of 254 nm UV, when measured at a distance of 7.0 cm. This dose of UV was found to be lethal to both repair-deficient E. coli bacteria and repair-deficient human skin fibroblasts obtained from xeroderma pigmentosum donors, as well as mutagenic in B/r wild-type and HCR-mutant bacteria. (Author)

  15. UV-LED Curing Efficiency of Wood Coatings

    Directory of Open Access Journals (Sweden)

    Véronic Landry

    2015-12-01

    Full Text Available Ultraviolet light emitting diodes (UV-LEDs have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerful enough to cure UV high solids acrylate coatings while satisfactory results can be obtained for UV water-based formulations. In fact, conversion percentages were found to be low for the high solids coatings, leaving the coatings tacky. Higher conversion percentages were obtained for the UV water-based formulations. As a result, mass loss, hardness, and scratch resistance found for the samples cured by UV-LED were closed to the ones found for the samples cured using the UV microwave lamp.

  16. Hydrodynamic simulation of X-UV laser-produced plasmas

    International Nuclear Information System (INIS)

    Fajardo, M.; Zeitoun, P.; Gauthier, J.C.

    2004-01-01

    With the construction of novel X-UV sources, such as V-UV FEL's (free-electron lasers), X-UV laser-matter interaction will become available at ultra-high intensities. But even table-top facilities such as X-UV lasers or High Harmonic Generation, are starting to reach intensities high enough to produce dense plasmas. X-UV laser-matter interaction is studied by a 1-dimensional hydrodynamic Lagrangian code with radiative transfer for a range of interesting X-UV sources. Heating is found to be very different for Z=12-14 elements having L-edges around the X-UV laser wavelength. Possible absorption mechanisms were investigated in order to explain this behaviour, and interaction with cold dense matter proved to be dominant. Plasma sensitivity to X-UV laser parameters such as energy, pulse duration, and wavelength was also studied, covering ranges of existing X-UV lasers. We found that X-UV laser-produced plasmas could be studied using table-top lasers, paving the way for future V-UV-FEL high intensity experiments. (authors)

  17. Effects of UV irradiation on a living skin equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D; Gay, R J [Organogenesis Incorporated, Camton, MA (United States)

    1993-05-01

    The Living Skin Equivalent is an organotypic coculture composed of human dermal fibroblasts interspersed in a collagen-containing matrix and overlaid with human keratinocytes forming a stratified epidermis. The LSE has a dry, air-exposed epidermal surface suitable for the application of oils, creams and emulsions. The protective effects of an 8% homosylate standard and of five UV-A sunscreens, topically applied to the LSE, were determined and compared with their reported protection factors in human skin. Morphological changes and the release of proinflammatory mediators (interleukin-1-''alpha, tumor necrosis factor-[alpha] and prostaglandin E2) implicated in UV-induced erythema were also demonstrated in the LSE exposed to UV-A or UV-B. The data suggest that the LSE can be used for studying the effects of UV radiation on skin and may have utility for assessing the efficacy of certain sunscreens against UV-B and UV-A. (Author).

  18. Practical aspects of irradiance and energy in UV curing

    International Nuclear Information System (INIS)

    Stowe, R.W.

    1999-01-01

    The physical properties of UV-cured materials are substantially affected by the lamp systems used to cure them. The development of the intended properties, whether a varnish, an ink, or an adhesive, can depend on how well these lamp factors are designed and managed. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, effective energy (time-integrated UV irradiance), and infrared radiation. Inks and varnishes will exhibit very different response to peak irradiance or energy, as well as to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable materials, widens the range in which UV curing is a faster, more efficient production process. This paper explores the reasons for clearly identifying these factors for process optimization

  19. Effects of UV irradiation on a living skin equivalent

    International Nuclear Information System (INIS)

    Nelson, D.; Gay, R.J.

    1993-01-01

    The Living Skin Equivalent is an organotypic coculture composed of human dermal fibroblasts interspersed in a collagen-containing matrix and overlaid with human keratinocytes forming a stratified epidermis. The LSE has a dry, air-exposed epidermal surface suitable for the application of oils, creams and emulsions. The protective effects of an 8% homosylate standard and of five UV-A sunscreens, topically applied to the LSE, were determined and compared with their reported protection factors in human skin. Morphological changes and the release of proinflammatory mediators (interleukin-1-''alpha, tumor necrosis factor-α and prostaglandin E2) implicated in UV-induced erythema were also demonstrated in the LSE exposed to UV-A or UV-B. The data suggest that the LSE can be used for studying the effects of UV radiation on skin and may have utility for assessing the efficacy of certain sunscreens against UV-B and UV-A. (Author)

  20. Les édifices néogothiques parisiens et leurs verrières : églises et chapelles catholiques

    Directory of Open Access Journals (Sweden)

    Martine Callias Bey

    2012-04-01

    Full Text Available Malgré l’intérêt porté aux œuvres d’art religieuses du XIXe siècle depuis une trentaine d’années, beaucoup de vitraux religieux du XIXe siècle ont déjà disparu à Paris ; il s’avère donc urgent de les inventorier. L’objet de l’article qui suit est la présentation des édifices catholiques parisiens de style néogothique et de leurs verrières. Ce corpus comprend 5 églises paroissiales, 19 chapelles de congrégations ou anciennes chapelles devenues paroisses, et deux bâtiments annexes. Sur 526 verrières étudiées, 286 sont ornées de figures ou de scènes dont 37 entrent dans la catégorie vitrail-tableau ; les 240 autres verrières sont ornementales. 22 ateliers sont à l’origine de ces verrières, parmi les plus importants tels Didron, Lusson, Champigneulle, Hirsch, Gsell, etc. L’on sait que Paris a joué un rôle déterminant dans la renaissance du vitrail durant le premier tiers du XIXe siècle, grâce à la perspicacité de certains hommes de pouvoir comme le comte de Chabrol qui fut à l’origine de la « résurrection » du métier de peintre verrier avec la création du premier atelier de la Foire Saint-Laurent en 1825, grâce également à la confrontation des archéologues avec les premiers grands chantiers de restauration et le rôle décisif des architectes diocésains. L’iconographie de ces verrières reflète l’évolution du contexte religieux, de la liberté concordataire à l’explosion congrégationniste, du retour de l’autorité romaine au triomphe de l’ultramontanisme, du mouvement anticongrégationniste à la loi de Séparation de 1905. Le vitrail néogothique épouse plutôt une iconographie de tendance gallicane, teintée d’un certain « romantisme » ; mais à partir de 1850, il s’ouvre à de nouvelles images et devient ce que l’on pourrait appeler un « moyen de propagande ». Le vitrail néogothique marque le retour à la couleur ; l’imitation des Anciens exige

  1. Ciprofloxacin oxidation by UV-C activated peroxymonosulfate in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi-Ahmed, Moussa; Chiron, Serge, E-mail: Serge.Chiron@msem.univ-montp2.fr

    2014-01-30

    Highlights: • UV/PMS more efficient than UV/H{sub 2}O{sub 2} for ciprofloxacin removal in wastewater. • PMS decomposition into sulfate radical was activated by bicarbonate ions. • CIP degradation pathways elucidation support sulfate radical attacks as a main route. • Sulfate radical generation allows for CIP antibacterial activity elimination. -- Abstract: This work aimed at demonstrating the advantages to use sulfate radical anion for eliminating ciprofloxacin residues from treated domestic wastewater by comparing three UV-254 nm based advanced oxidation processes: UV/persulfate (PDS), UV/peroxymonosulfate (PMS) and UV/H{sub 2}O{sub 2}. In distilled water, the order of efficiency was UV/PDS > UV/PMS > UV/H{sub 2}O{sub 2} while in wastewater, the most efficient process was UV/PMS followed by UV/PDS and UV/H{sub 2}O{sub 2} mainly because PMS decomposition into sulfate radical anion was activated by bicarbonate ions. CIP was fully degraded in wastewater at pH 7 in 60 min for a [PMS]/[CIP] molar ratio of 20. Nine transformation products were identified by liquid chromatography–high resolution-mass spectrometry allowing for the establishment of degradation pathways in the UV/PMS system. Sulfate radical anion attacks prompted transformations at the piperazinyl ring through a one electron oxidation mechanism as a major pathway while hydroxyl radical attacks were mainly responsible for quinolone moiety transformations as a minor pathway. Sulfate radical anion generation has made UV/PMS a kinetically effective process in removing ciprofloxacin from wastewater with the elimination of ciprofloxacin antibacterial activity.

  2. Ciprofloxacin oxidation by UV-C activated peroxymonosulfate in wastewater

    International Nuclear Information System (INIS)

    Mahdi-Ahmed, Moussa; Chiron, Serge

    2014-01-01

    Highlights: • UV/PMS more efficient than UV/H 2 O 2 for ciprofloxacin removal in wastewater. • PMS decomposition into sulfate radical was activated by bicarbonate ions. • CIP degradation pathways elucidation support sulfate radical attacks as a main route. • Sulfate radical generation allows for CIP antibacterial activity elimination. -- Abstract: This work aimed at demonstrating the advantages to use sulfate radical anion for eliminating ciprofloxacin residues from treated domestic wastewater by comparing three UV-254 nm based advanced oxidation processes: UV/persulfate (PDS), UV/peroxymonosulfate (PMS) and UV/H 2 O 2 . In distilled water, the order of efficiency was UV/PDS > UV/PMS > UV/H 2 O 2 while in wastewater, the most efficient process was UV/PMS followed by UV/PDS and UV/H 2 O 2 mainly because PMS decomposition into sulfate radical anion was activated by bicarbonate ions. CIP was fully degraded in wastewater at pH 7 in 60 min for a [PMS]/[CIP] molar ratio of 20. Nine transformation products were identified by liquid chromatography–high resolution-mass spectrometry allowing for the establishment of degradation pathways in the UV/PMS system. Sulfate radical anion attacks prompted transformations at the piperazinyl ring through a one electron oxidation mechanism as a major pathway while hydroxyl radical attacks were mainly responsible for quinolone moiety transformations as a minor pathway. Sulfate radical anion generation has made UV/PMS a kinetically effective process in removing ciprofloxacin from wastewater with the elimination of ciprofloxacin antibacterial activity

  3. Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, R.M.B. [Universidade Tecnica, Lisbon (Portugal). Inst. Superior de Agronomia]|[Universidade Nova de Lisboa, Oeiras (Portugal). Instituto de Tecnologia Quimica e Biologica; Franco, E.; Teixeira, A.R.N. [Universidade Tecnica, Lisbon (Portugal). Inst. Superior de Agronomia

    1996-08-15

    The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a 65 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of {sup 35}S-labelled ribulose biphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose biphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose biphosphate carboxylase. For short periods of time (<1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose biphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photosynthetic tissues. (Author).

  4. Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation

    International Nuclear Information System (INIS)

    Ferreira, R.M.B.; Universidade Nova de Lisboa, Oeiras; Franco, E.; Teixeira, A.R.N.

    1996-01-01

    The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a 65 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35 S-labelled ribulose biphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose biphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose biphosphate carboxylase. For short periods of time (<1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose biphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photosynthetic tissues. (Author)

  5. Quality assessment of solar UV irradiance measured with array spectroradiometers

    Science.gov (United States)

    Egli, Luca; Gröbner, Julian; Hülsen, Gregor; Bachmann, Luciano; Blumthaler, Mario; Dubard, Jimmy; Khazova, Marina; Kift, Richard; Hoogendijk, Kees; Serrano, Antonio; Smedley, Andrew; Vilaplana, José-Manuel

    2016-04-01

    The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance measurements. Within the European EMRP ENV03 project "Solar UV", new devices, guidelines and characterization methods have been developed to improve solar UV measurements with ASRMs, and support to the end user community has been provided. In order to assess the quality of 14 end user ASRMs, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the blind intercomparison revealed that ASRMs, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema-weighted UV index - in particular at large solar zenith angles - due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available ASRMs within 5 % compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range of solar zenith angles. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 and 400 nm under all atmospheric conditions.

  6. UV drinking water disinfection with photovoltaic power supply. UV-Trinkwasserentkeimung mit photovoltaischer Stromversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Scharmer, K; Pappers, B; Guenner, C

    1990-06-01

    The study carried out on commission of the BMFT describes in the first three chapters UV disinfectation systems as well as experience gained from their use in industry and developing countries. In the chapter 4-7 special requirements for the use in developing countries are specified and compared to the results of other projects of the BMFT, GTZ and UNIDO. Chapter 5 gives a matrix of cost in which UV and chlorine disinfectation are compared to each other. In the final chapters 8 and 9 test programs and laboratory tests are described which are to serve as basis for planned field tests. (ORU).

  7. Hybrid 2D patterning using UV laser direct writing and aerosol jet printing of UV curable polydimethylsiloxane

    Science.gov (United States)

    Obata, Kotaro; Schonewille, Adam; Slobin, Shayna; Hohnholz, Arndt; Unger, Claudia; Koch, Jürgen; Suttmann, Oliver; Overmeyer, Ludger

    2017-09-01

    The hybrid technique of aerosol jet printing and ultraviolet (UV) laser direct writing was developed for 2D patterning of thin film UV curable polydimethylsiloxane (PDMS). A dual atomizer module in an aerosol jet printing system generated aerosol jet streams from material components of the UV curable PDMS individually and enables the mixing in a controlled ratio. Precise control of the aerosol jet printing achieved the layer thickness of UV curable PDMS as thin as 1.6 μm. This aerosol jet printing system is advantageous because of its ability to print uniform thin-film coatings of UV curable PDMS on planar surfaces as well as free-form surfaces without the use of solvents. In addition, the hybrid 2D patterning using the combination of UV laser direct writing and aerosol jet printing achieved selective photo-initiated polymerization of the UV curable PDMS layer with an X-Y resolution of 17.5 μm.

  8. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    International Nuclear Information System (INIS)

    Silva Filho, F.C.; Elias, C.A.; Souza, W. de

    1986-01-01

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells. (author)

  9. TAUVEX UV imager on the SRG

    Science.gov (United States)

    Brosch, Noah; Shemi, Amotz; Netzer, Hagai; Blasberger, Avigdor; Topaz, Jeremy M.

    1994-11-01

    The TAUVEX space astronomy experiment to image wide sky areas in the 140 - 280 nm spectral region is part of the SODART telescope complex on SRG, and functions as a separate scientific instrument and as a service system for the spacecraft. The experiment consists of three bore-sighted telescopes with 20 cm diameter Ritchey-Chretien optics. Each telescope is equipped with a four-position filter wheel and can select one of six UV bands in the spectral region of operation. The photon-counting, imaging detectors cover a field of view of 0 degree(s).9, with 80% of the energy from a point source within about 10 arcsec. The image is sampled at 3 arcsec intervals. The sensitivity is such that stars of 10 - 11 mag in the UV are detected in 2 sec, and in a typical SRG pointing of 5 hours stars as faint as 20 mag are detectable. TAUVEX provides off-line aspect solutions for the SODART focal plane instruments and on-line fine pointing information to the SRG attitude and control system. The experiment is constructed by El-Op, Electro-Optical Industries Ltd., and is financially supported by the Government of Israel, through the Israel Space Agency and the Ministry of Science and Arts. By mid-1994 four models of TAUVEX had been produced and supplied to the SRG integrators: size and mass models in 1992, a thermal model in early 1993 and an engineering model in spring 1994. A qualification model is being tested intensively at El-Op these days and the flight model will be ready, after testing, burn-in and calibration, by the end of 1994. TAUVEX is a light-weight, low-power, versatile UV imaging experiment with significant redundancy, which is not limited to operations on-board SRG. The system may operate on other platforms, including small satellites, if such an opportunity occurs.

  10. Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms.

    Science.gov (United States)

    Paul, Nigel D; Moore, Jason P; McPherson, Martin; Lambourne, Cathryn; Croft, Patricia; Heaton, Joanna C; Wargent, Jason J

    2012-08-01

    Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation. Copyright © Physiologia Plantarum 2011.

  11. UV/EB curing in Australia

    International Nuclear Information System (INIS)

    Woods, R.; Garnett, J.; Loo Teck Ng

    1999-01-01

    Progress in LTV/EB curing is reviewed in Australia. Generally the technology is used by those industries where curing is well developed in Europe and North America, however the scale is an order of magnitude lower due to the smaller market size. The Asian economic crisis does not appear to have affected expansion of the technology in Australia. EB continues to be successfully used in the packaging and foam fields whilst in UV, security devices, particularly banknotes are steadily expanding especially in export markets have been studied

  12. New stratospheric UV/visible radiance measurements

    Directory of Open Access Journals (Sweden)

    F. J. Marceau

    1994-01-01

    Full Text Available A stratospheric balloon was launched on 12 October 1986 from the "CNES" base at Aire sur l'Adour (France to record twilight radiance in the stratosphere. The near-UV and visible radiances were continuously monitored by a photometer during sunrise. Some observations are presented for different viewing azimuthal planes and viewing elevation angles. They show the influence of aerosols layers and clouds which can be also seen on related photographs. The results as a whole may be used for testing some radiative models, especially for twilight conditions.

  13. Stringy horizons and UV/IR mixing

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Israel, Roy [Physics Department, Tel-Aviv University Israel,Ramat-Aviv, 69978 (Israel); Giveon, Amit [Racah Institute of Physics, The Hebrew University,Jerusalem, 91904 (Israel); Itzhaki, Nissan; Liram, Lior [Physics Department, Tel-Aviv University Israel,Ramat-Aviv, 69978 (Israel)

    2015-11-24

    The target-space interpretation of the exact (in α{sup ′}) reflection coefficient for scattering from Euclidean black-hole horizons in classical string theory is studied. For concreteness, we focus on the solvable SL(2,ℝ){sub k}/U(1) black hole. It is shown that it exhibits a fascinating UV/IR mixing, dramatically modifying the late-time behavior of general relativity. We speculate that this might play an important role in the black-hole information puzzle, as well as in clarifying features related with the non-locality of Little String Theory.

  14. Hazards To The Eye From UV

    Science.gov (United States)

    Zuclich, Joseph A.

    1980-10-01

    Ocular effects of ultraviolet radiation, 200-400 nm, are reviewed. Depending upon the exposure parameter involved, UV radiation may be harmful to the cornea, lens and/or retina. Ranges of exposure parameters (wavelength, exposure duration, etc.) for which each of the tissues is susceptible are specified and the nature of the tissue is described. Present understanding of the thermal and photochemical damage mechanism operative for various conditions of exposure are discussed Ocular damage thresholds for wide ranges of exposure parameters are summarized and compared to existing safety standards.

  15. UV/EB curing market in Indonesia

    International Nuclear Information System (INIS)

    Hilmy, N.; Danu, S.

    1999-01-01

    The most application of UV curing of surface coating in Indonesia are on fancy plywood, furniture and wood flooring industry. Other application are on papers, printing ink/labelling, printed circuit board/PCB and dental materials. At present, application of EB curing coating is still in a pilot plant scale due to the high cost of production. Limited number of application of EB curing by using low energy electron beam machine are on wood panels, ceramics and marbles. This paper describes the market and the problem faced by the largest user of radiation curing systems such as the secondary process plywood, furniture and paper industries

  16. UV curable aqueous dispersions for wood coatings

    International Nuclear Information System (INIS)

    Peeters, S.; Bleus, J.P.; Wang, Z.J.; Arceneaux, J. A.; Hall, J.

    1999-01-01

    In this paper the characterisation of aqueous dispersions of UV curable resins is described. Two types of dispersions were used: dispersions that are tacky after water evaporation and tack - free before cure dispersions. The physical and rheological properties of these products have been determined and the performance of these dispersions in various formulations, especially for wood applications has been studied. With these dispersions, it is possible to produce coatings having a good cure speed, good surface hardness and good solvent -, chemical - and water resistance

  17. UV Irradiance Enhancements by Scattering of Solar Radiation from Clouds

    Directory of Open Access Journals (Sweden)

    Uwe Feister

    2015-08-01

    Full Text Available Scattering of solar radiation by clouds can reduce or enhance solar global irradiance compared to cloudless-sky irradiance at the Earth’s surface. Cloud effects to global irradiance can be described by Cloud Modification Factors (CMF. Depending on strength and duration, irradiance enhancements affect the energy balance of the surface and gain of solar power for electric energy generation. In the ultraviolet region, they increase the risk for damage to living organisms. Wavelength-dependent CMFs have been shown to reach 1.5 even in the UV-B region at low altitudes. Ground-based solar radiation measurements in the high Andes region at altitudes up to 5917 m a.s.l showed cloud-induced irradiance enhancements. While UV-A enhancements were explained by cloud scattering, both radiation scattering from clouds and Negative Ozone Anomalies (NOA have been discussed to have caused short-time enhancement of UV-B irradiance. Based on scenarios using published CMF and additional spectroradiometric measurements at a low-altitude site, the contribution of cloud scattering to the UV-B irradiance enhancement in the Andes region has been estimated. The range of UV index estimates converted from measured UV-B and UV-A irradiance and modeled cloudless-sky ratios UV-B/erythemal UV is compatible with an earlier estimate of an extreme UV index value of 43 derived for the high Andes.

  18. La politique criminelle en matière de violences conjugales : une évaluation des pratiques judiciaires et de leurs effets en termes de récidive

    OpenAIRE

    Vanneste, Charlotte

    2016-01-01

    La politique criminelle en matière de violences conjugales : une évaluation des pratiques judiciaires et de leurs effets en termes de récidive La recherche demandée par le Collège des Procureurs généraux visait à évaluer les pratiques judiciaires développées en matière de violences conjugales en application des directives de politique criminelle données par la circulaire COL 4/2006. Pour ce faire, les données statistiques relatives à l’ensemble des prévenus signalés au moins une fois aux ...

  19. Les mécanismes des réductions budgétaires et leurs conséquences sur la diffusion de la langue française : Analyse de la situation en 2013

    Directory of Open Access Journals (Sweden)

    Frédéric Mazières

    2013-12-01

    Full Text Available Considérer la diplomatie linguistique sans se référer aux crédits qui l’alimentent peut entraîner des erreurs d’appréciation. On évoque souvent les budgets linguistiques sans vraiment connaître leurs modalités de fonctionnement. La qualité et l’efficacité de la diffusion de la langue française dépendent des paramètres didactiques, soit, mais aussi des paramètres budgétaires. Nous retrouvons un des axes « méta-didactiques » de la diffusion linguistique. Cet article est, au moins, l’occasion d’une explication des modalités budgétaires de la diffusion linguistique.

  20. Gestion patrimoniale des réseaux d’assainissement : de l’état des réseaux à la planification de leur réhabilitation − Outils, méthodes et perspectives

    Directory of Open Access Journals (Sweden)

    WEREY, Cathy ; LE GAT, Yves ; LE GAUFFRE, Pascal ; ROZAN, Anne ; WITTNER, Christophe ; NIRSIMLOO, Kévin ; LECLERC, Cyril

    2012-12-01

    Full Text Available En France, la gestion patrimoniale des réseaux d’assainissement est une préoccupation croissante. Certains réseaux commencent en effet à dater et vont nécessiter des renouvellements importants et coûteux pour les décennies à venir. À travers leur mise en œuvre sur les réseaux de Caen et de Bordeaux, cet article présente deux modèles complémentaires, Indigau et GompitZ, permettant de décrire l’état du réseau et de prioriser les tronçons à réhabiliter.

  1. Absorption spectra between 0.8 {mu} and 30 {mu} of mixtures of H{sub 2}O - D{sub 2}O in the liquid state; Le spectre d'absorption des melanges H{sub 2}O-D{sub 2}O a l'etat liquide entre 0,8 et 30 {mu}

    Energy Technology Data Exchange (ETDEWEB)

    Ceccaldi, M; Goldman, M; Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    There has been very little work carried out recently on the absorption bands of H{sub 2}O, HDO and D{sub 2}O in the liquid state. We have established the spectra of these molecules in between 0.8 and 30 p. The table of absorption bands of the molecules HDO and D{sub 2}O for which all the bands corresponding to those for H{sub 2}O had not been established has been completed. We have sought a convenient method of representing the variations in optical density of certain HDO bands as a function of the concentration of heavy water in the mixtures studied. (author) [French] Il y a peu de travaux recents sur les bandes d'absorption de H{sub 2}O, HDO et D{sub 2}O a l'etat liquide. Nous avons releve les spectres de ces molecules entre 0,8 et 30 p. Le tableau des bandes d'absorption des molecules HDO et D{sub 2}O, pour lesquelles le releve de toutes les bandes correspondantes a celles de H{sub 2}O n'etait pas encore effectue, a ete complete. Nous avons cherche des modes de representation commodes des variations de densite optique de certaines bandes de HDO en fonction de la teneur en eau lourde des melanges etudies. (auteur)

  2. Transcriptional and cellular effects of benzotriazole UV stabilizers UV-234 and UV-328 in the freshwater invertebrates Chlamydomonas reinhardtii and Daphnia magna.

    Science.gov (United States)

    Giraudo, Maeva; Cottin, Guillaume; Esperanza, Marta; Gagnon, Pierre; Silva, Amila O De; Houde, Magali

    2017-12-01

    Benzotriazole ultra violet stabilizers (BZT-UVs) are compounds used in many applications and products to prevent photochemical degradation. Despite their widespread presence in aquatic ecosystems and persistence in the environment, there are very limited data on their effects and toxicity, and their modes of action remain largely unknown. The objectives of the present study were to evaluate the chronic effects of 2 BZT-UVs, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), on the freshwater green algae Chlamydomonas reinhardtii and the freshwater crustacean Daphnia magna. Organisms were exposed to 0.01 and 10 μg/L of UV-234, UV-328, as well as a mixture of the 2 compounds. Life-history endpoints (viability, reproduction, and growth) and oxidative stress-related biomarkers (gene transcription, reactive oxygen species [ROS] production, and lipid peroxidation) were measured. Daphnia magna growth, reproduction, and gene transcription were not impacted by 21-d individual or mixed exposure. After 96-h of exposure, no differences were observed on the cellular viability of C. reinhardtii for either of the 2 BZT-UVs. In the algae, results showed increased ROS production in response to UV-328 and lipid peroxidation following exposure to UV-234. Synergistic effects of the 2 BZT-UVs were evident at the transcriptional level with 2 to 6 times up-regulation of glutathione peroxidase (gp x ) in response to the mixture for all treatment conditions. The transcription of superoxide dismutase (sod), catalase (cat), and ascorbic peroxidase (apx) was also regulated by UV-234 and UV-328 in the green algae, most likely as a result of ROS production and lipid peroxidation. Results from the present study suggest potential impacts of UV-234 and UV-328 exposure on the antioxidant defense system in C. reinhardtii. Environ Toxicol Chem 2017;36:3333-3342. © 2017 Crown in the Right of Canada. Published by

  3. De la nécessité pour les femmes chirurgiens de « faire leurs preuves » Why female surgeons need to “prove themselves”. Professional overinvestment and pregnancy

    Directory of Open Access Journals (Sweden)

    Emmanuelle Zolesio

    2011-06-01

    Full Text Available L’objectif de cet article est de voir les obstacles qui existent à la féminisation de la chirurgie, encore aujourd’hui. Quoique la médecine dans son ensemble se féminise, la chirurgie demeure la spécialité médicale la plus sous-féminisée et les comportements sexistes des professionnels en poste ne sont pas pour rien dans cet état de fait comme le montre notre enquête ethnographique. En effet, les internes filles en chirurgie sont systématiquement suspectées d’un moindre investissement professionnel du fait de leur statut potentiel de mère, discréditées d’avance quant à leurs capacités physiques, jugées enfin trop fragiles émotionnellement pour « tenir » dans un métier difficile.The purpose of this paper is to underline the remaining obstacles to the feminization of surgery. An ethnographic study shows that, although the feminization of medicine as a whole is real, surgery remains the most under-feminized area of medical specialization and sexist behaviors from senior surgeons are partly responsible for this situation. In fact, female students in surgery are always suspected of being less involved in their jobs as they are potential mothers, they are discredited in advance in matters of physical capacities, and are considered as too weak emotionally to “cope” in this difficult profession.

  4. Influence des conditions d'élevage et de sulfitage des vins rouges en barriques sur leur teneur en acide acétique et en éthyl-phenols

    Directory of Open Access Journals (Sweden)

    Pascal Chatonnet

    1993-12-01

    En plus de la dose, les conditions de sulfitage des vins et des barriques sont également importantes. L'apport d'une quantité de SO2 non inférieure à 7 g par fût sous forme gazeuse dans un fût vide permet simultanément la désinfection des douelles et le sulfitage des vins. A dosage identique, avec un sulfitage direct du vin, le développement de Brettanomyces intermedius n'est pas inhibé et les vins risquent de présenter un caractère phénolé désagréable en fin d'élevage. Par ailleurs, les sulfitages à la mèche ou à la pastille ne possèdent pas la même efficacité. Si à quantité de soufre identique le méchage à la pastille procure un sulfitage presque deux fois plus important, selon l'origine et les méthodes de fabrication employées, les pastilles de soufre possèdent une stabilité au vieillissement variable se traduisant par des sulfitages irréguliers en fonction de leur âge et de leurs conditions de stockage. La présence d'une charge non combustible hygroscopique entrant dans la composition de certaines pastilles de soufre est responsable de cette instabilité.

  5. Les proportions des verbes SAY/DIRE/ŘÍCI dans les propositions incises et leurs équivalents en traduction : étude sur corpus parallèle

    Directory of Open Access Journals (Sweden)

    Olga Nádvorníková

    2017-10-01

    Full Text Available EN: The aim of this paper is to identify and compare the distribution of the verbs say/dire/říci-říkat in reporting clauses placed medially or finally, and to analyze types of their equivalents in translations (French-English-Czech. Our hypothesis is that in translations from a language with a higher proportion of the neutral verbs say/dire/říci-říkat in reporting clauses into a language where their proportion is lower, the number of replacements of these verbs, especially using explicitation, will be higher than in the opposite direction of translation. The analysis is based on fiction texts from the InterCorp parallel corpus. FR: L’objectif du présent article est d’identifier et de comparer les proportions des verbes say/dire/ří- ci-říkat dans les propositions incises et d’analyser les types de leurs équivalents en traduction (français-anglais-tchèque. Nous avançons l’hypothèse que dans les traductions depuis des langues à proportion élevée de ces verbes de dire neutres dans les incises vers les langues où leur proportion s’avère moins élevée, les traducteurs auront davantage recours à l’explicitation ou à d’autres remplacements du verbe de dire neutre que dans l’autre sens de la traduction. L’analyse est basée sur le corpus parallèle InterCorp, limité aux textes littéraires.

  6. Comments on a Method to Measure Sucralose Using UV Photodegradation Followed by UV Spectrophotometry.

    Science.gov (United States)

    Fang, Te; Andrews, Susan A; Hofmann, Ron

    2017-05-01

    A simple and quick method to measure sucralose in aqueous solution at concentrations in the order of 0.1-1.2 g·L-1 proposed by Idris et al. uses UV irradiation prior to UV spectrophotometry. The photolysis of sucralose forms a photoactive compound characterized by maximum absorbance at approximately 270 nm. The conditions required for sucralose photolysis, however, had not been completely reported. In this work, the procedure described by Idris et al. was replicated using a low-pressure UV lamp to irradiate sucralose samples with a wider range of initial concentrations (0.04-10 g·L-1) with known fluences. It was determined that care must be taken to ensure that the same fluence is applied for both calibration and measurement steps because the absorbance of the sucralose photolysis product is a function of the applied fluence. The way the samples are irradiated also has an impact on the results in that the method exhibits a greater linear range if an apparatus is used that maximizes the fluence rate (e.g., by placing samples closer to the UV source or using a higher-intensity lamp).

  7. Capillary electrophoresis hyphenated with UV-native-laser induced fluorescence detection (CE/UV-native-LIF).

    Science.gov (United States)

    Couderc, François; Ong-Meang, Varravaddheay; Poinsot, Véréna

    2017-01-01

    Native laser-induced fluorescence using UV lasers associated to CE offers now a large related literature, for now 30 years. The main works have been performed using very expensive Ar-ion lasers emitting at 257 and 275 nm. They are not affordable for routine analyses, but have numerous applications such as protein, catecholamine, and indolamine analysis. Some other lasers such as HeCd 325 nm have been used but only for few applications. Diode lasers, emitting at 266 nm, cheaper, are extensively used for the same topics, even if the obtained sensitivity is lower than the one observed using the costly UV-Ar-ion lasers. This review presents various CE or microchips applications and different UV lasers used for the excitation of native fluorescence. We showed that CE/Native UV laser induced fluorescence detection is very sensitive for detection as well as small aromatic biomolecules than proteins containing Trp and Tyr amino acids. Moreover, it is a simple way to analyze biomolecules without derivatization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. UV/Visible Telescope with Hubble Disposal

    Science.gov (United States)

    Benford, Dominic J.

    2013-01-01

    Submission Overview: Our primary objective is to convey a sense of the significant advances possible in astrophysics investigations for major Cosmic Origins COR program goals with a 2.4m telescope asset outfitted with one or more advanced UV visible instruments. Several compelling science objectives were identified based on community meetings these science objectives drove the conceptual design of instruments studied by the COR Program Office during July September 2012. This RFI submission encapsulates the results of that study, and suggests that a more detailed look into the instrument suite should be conducted to prove viability and affordability to support the demonstrated scientific value. This study was conducted in the context of a larger effort to consider the options available for a mission to dispose safely of Hubble hence, the overall architecture considered for the mission we studied for the 2.4m telescope asset included resource sharing. This mitigates combined cost and risk and provides naturally for a continued US leadership role in astrophysics with an advanced, general-purpose UV visible space telescope.

  9. Contribution to Casein Determination by UV Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Stefanescu Raluca

    2017-12-01

    Full Text Available In the present paper, the interaction between copper ions and proteins is presented, in order to elaborate a simple and rapid spectrophotometric assay of casein in milk. Under alkaline conditions, copper ions form the biuret complex with the proteins, which can be used in protein determination. Although very specific, the biuret method is less sensitive. Using insoluble copper phosphate, casein is able to extract copper ions, with which it forms the biuret complex, while either the complex or copper ions could be determined in the ultraviolet range. Indeed, an increased absorbance of biuret complex at 215 nm was found. Nevertheless, copper ions can be determined in UV as well, their concentration being proportional to that of casein. When used tetraglycine instead casein, mass spectrometric measurements at pH higher than 11 revealed the formation of complexes with many copper ions bound to each peptide bond-containing molecule. Nevertheless, on diluting the biuret solution the complex may dissociate leading to very complex UV spectra that should be further studied.

  10. UV/visible albedos from airborne measurements

    Science.gov (United States)

    Webb, A.; Kylling, A.; Stromberg, I.

    2003-04-01

    During the INSPECTRO campaign effective surface albedo was measured at UV and visible wavelengths from two airborne platforms, a Cessna light aircraft and a hot air balloon. On board the Cessna was a scanning spectroradiometer measuring from 300 - 500nm at 10nm intervals. The NILU cube, with 6 faces and two UV channels at 312 and 340nm, was suspended beneath the hot air balloon. Flights took place over East Anglia during September, 2002. Balloon flights were made below cloud layers, while the Cessna flew both above and below cloud. The Cessna also flew over Barton Bendish, where surface albedos have been measured for ground truthing of satellite data, and measured the effective albedo at four visible wave- lengths in the centres of the satellite bandpass functions. Results of measurements from the different platforms are compared, and model simulations used to deduce the surface albedo from the effective albedo at altitude, giving, for example, an albedo of 0.02 ± 0.01 at 340nm.

  11. Delayed expression of enhanced reactivation and decreased mutagenesis of UV-irradiated adenovirus in UV-irradiated ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Bennett, C.B.; Rainbow, A.J.

    1988-01-01

    In this study the authors examined UV-enhanced reactivation (UVER) and UV-enhanced mutagenesis (UVEM) of UV-irradiated adenovirus in AT fibroblasts. UVER factors for Ad V antigen expression were significantly less than normal in AT strains tested when infection occurred immediately after UV-irradiation of cells. However, UVER factors were >1 and similar to those found for normal strains when cells were infected 24 h after UV-irradiation, indicating delay in the expression of UVER for Ad V antigen in AT cells. UV-irradiation of both normal and AT cells 24 h prior to infection also resulted in a significant increase in progeny survival for UV-irradiated Ad. In normal cells, this progeny UVER was concomitant with a significant increase in the mutation frequency for UV-irradiated virus (increase in targeted mutagenesis) suggesting existence of an inducible error-prone DNA repair mode in normal human cells. In contrast, pre-UV-irradiation of AT cells resulted in a significant decrease in the mutation frequency for UV-irradiated virus. (author)

  12. Protective effects of polyamines against UV-A and UV-B illumination in Physcia semipinnata thalli

    Directory of Open Access Journals (Sweden)

    Esmer Işıl

    2017-04-01

    Full Text Available The damage to DNA induced by UV-A and UV-B and protective effects of the polyamines putrescine (put, spermidine (spd and spermine (spm were investigated on the lichen Physcia semipinnata in the present study. Our results suggest that significant alterations of the photosynthetic quantum yield ratio occurred in response to increased UV-A and UV-B exposure time. The photosynthetic quantum yield ratio gradually decreased in P. semipinnata following exposure to UV-A and UV-B. Physcia semipinnata thalli which were treated with a polyamine in a concentration of 1 mM were not affected by UV-A exposure for 72 h. In the case of UV-B treatment, the protective polyamine dosage was 0.25 mM. We also used the random amplified polymorphic DNA (RAPD technique to detect DNA damage. The main changes observed in the RAPD profiles, which were obtained using 12 RAPD primers, were the appearance or disappearance of different bands and variation of their intensities. The use of at least three different primers allowed detection of specific band patterns in both UV-A- and UV-B-exposed samples treated with polyamines as compared to untreated ones.

  13. Is UV-A radiation a cause of malignant melanoma?

    International Nuclear Information System (INIS)

    Moan, J.

    1994-01-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs

  14. UV radiation dependent flavonoid accumulation of Cistus laurifolius L

    International Nuclear Information System (INIS)

    Vogt, T.; Gülz, P.-G.; Reznik, H.

    1991-01-01

    Epicuticular and intracellular flavonoids of Cistus laurifolius grown with and without UV radiation in a phytotron as well as under natural garden conditions in the field were studied. The amount of intracellular flavonoid glycosides of leaves receiving UV-A radiation was two fold higher than that measured in the absence o f UV-A radiation, whether grown in the phytotron or in the field. Exposure of previously protected leaves to UV-A radiation increased the intracellular flavonoid glycoside content to that of unprotected leaves. The qualitative composition of intracellular flavonoid glycosides showed a reduced amount of quercetin-3-galactoside to the myricetin monosides when the leaves were grown without UV-A radiation in the field and in the phytotron. Epicuticular flavonoid aglycones were not influenced by UV radiation significantly. (author)

  15. Development of UV absorbing PET through Electron Irradiation

    International Nuclear Information System (INIS)

    Kim, Jung Woo; Lee, Na Eun; Lim, Hyung San; Park, Yang Jeong; Cho, Sung Oh

    2017-01-01

    Experiment to increase UV absorbance through electron beam irradiation on PET was performed. Moreover, surface hardness and roughness of each sample were observed to find the key factor increasing UV absorbance. PET sheets were irradiated with an electron beam at various fluences. The irradiated samples, as well as pristine sample, were subjected to UV-visible spectral study(UV-Vis), pencil hardness test, and scanning electron microscopy(SEM) experiment. In this study, PET samples irradiated at several conditions were analyzed through various measurements. UV absorbance-another meaning of transmittance in this study- of irradiated PET sample increased compared with pristine sample as fluence was increased in UV-Visible spectroscopy experiment.

  16. Recent Advances on Endocrine Disrupting Effects of UV Filters

    Directory of Open Access Journals (Sweden)

    Jiaying Wang

    2016-08-01

    Full Text Available Ultraviolet (UV filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives.

  17. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...... observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks...... in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent...

  18. UV-irradiation enhances rice allelopathic potential in rhizosphere soil

    DEFF Research Database (Denmark)

    Mahmood, Khalid; Khan, Muhammad Bismillah; Song, Yuan Yuan

    2013-01-01

    Ultraviolet-B radiation is rising continuously due to stratospheric ozone depletion over temperate latitudes. This study investigated effects of UV exposure on rice allelopathic potentials. For this purpose, two rice (Oryza sativa L.) cultivars BR-41 (high allelopathic = able to inhibit neighboring...... grass and lettuce). These bioassays showed significant inhibition in lettuce and barnyard growth after UV in both rice cultivars. Interestingly, Huajingxian, which did not exhibit allelopathic potential in absence of UV showed significant inhibition after UV exposure. Phenolics, enzymes activities...... and genes responsible for biosynthesis of allelopathic compounds were examined after UV exposure. Phenolic compounds accumulated in rice leaves were quantified through HPLC analysis. They were significantly higher in BR-41 leaves after UV exposure. Enzyme activities (PAL and C4H) were significantly higher...

  19. Benchmark studies of UV-vis spectra simulation for cinnamates with UV filter profile.

    Science.gov (United States)

    Garcia, Ricardo D'A; Maltarollo, Vinícius G; Honório, Káthia M; Trossini, Gustavo H G

    2015-06-01

    Skin cancer is a serious public health problem worldwide, being incident over all five continents and affecting an increasing number of people. As sunscreens are considered an important preventive measure, studies to develop better and safer sunscreens are crucial. Cinnamates are UVB filters with good efficiency and cost-benefit, therefore, their study could lead to the development of new UV filters. A benchmark to define the most suitable density functional theory (DFT) functional to predict UV-vis spectra for ethylhexyl methoxycinnamate was performed. Time-dependent DFT (TD-DFT) calculations were then carried out [B3LYP/6-311 + G(d,p) and B3P86/6-311 + G(d,p) in methanol environment] for seven cinammete derivatives implemented in the Gaussian 03 package. All DFT/TD-DFT simulations were performed after a conformational search with the Monte-Carlo method and MMFF94 force field. B3LYP and B3P86 functionals were better at reproducing closely the experimental spectra of ethylhexyl methoxycinnamate. Calculations of seven cinnamates showed a λmax of around 310 nm, corroborating literature reports. It was observed that the energy for the main electronic transition was around 3.95 eV and could be explained by electron delocalization on the aromatic ring and ester group, which is important to UV absorption. The methodology employed proved to be suitable for determination of the UV spectra of cinnamates and could be used as a tool for the development of novel UV filters.

  20. UV radiation sources for artificial skin tanning and protection

    International Nuclear Information System (INIS)

    Zivkovic, D.; Hrnjak, M.

    1999-01-01

    UV radiation sources for artificial tanning are more utilized at the last time. UV radiation is not harmless, so there are not safety devices for tanning. If people do not want to avoid exposure to their radiation, than it is necessary to take the prevention measure: strictly dose of UV radiation according to skin type, use of appropriate protective eye-wears and respect for inhibit of some medicaments and some cosmetic products use. (author)

  1. The effect of fullerols under UV on cell

    International Nuclear Information System (INIS)

    Li Yuguo; Zhao Qunfen; Li Qingnuan; Xu Jingying; Li Wenxin; Ni Jin; Han Ling; Gao Fu

    2004-01-01

    The UV radioprotective effect of fullerols, which was compared with the effect of C 60 -PVP, was studied using cultured L02 cells. The cell survivals were determined by MTT method, SOD and MDA also were studied with chemistric colorimetry. The results showed that fullerols can effectively protect cells from damage induced by UV irradiation. The mechanism could be assosiated with the ability of fullerols to behave as an antioxidant compound, then fullerols protected cell membrane from damage by UV radiation. (authors)

  2. The genetic architecture of UV floral patterning in sunflower.

    Science.gov (United States)

    Moyers, Brook T; Owens, Gregory L; Baute, Gregory J; Rieseberg, Loren H

    2017-07-01

    The patterning of floral ultraviolet (UV) pigmentation varies both intra- and interspecifically in sunflowers and many other plant species, impacts pollinator attraction, and can be critical to reproductive success and crop yields. However, the genetic basis for variation in UV patterning is largely unknown. This study examines the genetic architecture for proportional and absolute size of the UV bullseye in Helianthus argophyllus , a close relative of the domesticated sunflower. A camera modified to capture UV light (320-380 nm) was used to phenotype floral UV patterning in an F 2 mapping population, then quantitative trait loci (QTL) were identified using genotyping-by-sequencing and linkage mapping. The ability of these QTL to predict the UV patterning of natural population individuals was also assessed. Proportional UV pigmentation is additively controlled by six moderate effect QTL that are predictive of this phenotype in natural populations. In contrast, UV bullseye size is controlled by a single large effect QTL that also controls flowerhead size and co-localizes with a major flowering time QTL in Helianthus . The co-localization of the UV bullseye size QTL, flowerhead size QTL and a previously known flowering time QTL may indicate a single highly pleiotropic locus or several closely linked loci, which could inhibit UV bullseye size from responding to selection without change in correlated characters. The genetic architecture of proportional UV pigmentation is relatively simple and different from that of UV bullseye size, and so should be able to respond to natural or artificial selection independently. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  3. Polycrystalline diamond film UV detectors for excimer lasers

    International Nuclear Information System (INIS)

    Ralchenko, V G; Savel'ev, A V; Konov, Vitalii I; Mazzeo, G; Spaziani, F; Conte, G; Polyakov, V I

    2006-01-01

    Photoresistive metal-semiconductor-metal detectors based on polycrystalline diamond films are fabricated for recording cw and pulsed UV radiation. The detectors have a high spectral selectivity (the UV-to-VIS response ratio is ∼10 5 ) and a temporal resolution of the order of 10 9 s. 'Solar-blind' photostable diamond detectors are promising for applications in UV lithography, laser micromachining, medicine, and space research. (letters)

  4. Skin β-Endorphin Mediates Addiction to UV Light

    OpenAIRE

    Fell, Gillian L.; Robinson, Kathleen C.; Mao, Jianren; Woolf, Clifford J.; Fisher, David E.

    2014-01-01

    Ultraviolet light is an established carcinogen yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize Proopiomelanocortin that is processed to Melanocyte Stimulating Hormone, inducing tanning. We show that in rodents another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed, and reversed by pharmacologic op...

  5. AlN ceramics as a detector for UV exposure

    International Nuclear Information System (INIS)

    Trinkler, L.; Berzina, B.; Boetter-Jensen, L.; Christensen, P.; Palcevskis, E.

    1999-01-01

    AlN-Y 2 O 3 ceramics is proposed for application in the field of UV detection and dosimetry. Both thermoluminescence (TL) and optically stimulated luminescence (OSL) signals from the material have been studied after exposure to UV light. AlN-Y 2 O 3 ceramics demonstrates very high sensitivity to UV light over a broad spectral region. The TL is characterized by a linear dose dependence over a large range. The fading rate of the UV-induced TL and OSL signals on storage at room temperature is lower than in the case of exposure to ionizing irradiation. (au)

  6. Potential application of UV radiation processing in electronic packaging

    International Nuclear Information System (INIS)

    Ng Chee Mang; Lim Yoke Keem; Kumar, R.N.

    1999-01-01

    UV-curable epoxies have been formulated for use in place of the established heat cure epoxy systems for coating, adhesion and encapsulation of electronic devices. The UV-cured epoxy systems can be formulated to give comparable or even better physical and chemical properties than the more common heat cured systems. The UV systems offer significant advantage in very fast cure and hence very short production cycle time. UV systems can also be formulated to give desired properties of increased strength, high Tg, increased humidity resistance and improved temperature cycling performance

  7. Radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

    1993-10-01

    A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models

  8. UV-blocking potential of oils and juices.

    Science.gov (United States)

    Gause, S; Chauhan, A

    2016-08-01

    Sunscreens are commonly used to protect the body from damage caused by UV light. Some components of organic sunscreens have been shown to pass through the skin during wear which could raise toxicity concerns for these compounds. This study explores the potential for oils and fruit and vegetable juices to be substitutes for these compounds. The absorptivity of various oils (canola oil, citronella oil, coconut oil, olive oil, soya bean oil, vitamin E, as well as aloe vera) and fruit and vegetable juices (acerola, beet, grape, orange carrot, purple carrot and raspberry) was measured in vitro. The mean absorptivity was compared with FDA-approved UV absorbers to gauge the potential of the natural products. The most promising candidates were incorporated into formulations, and the UV transmittance of a 20-μm-thick film of the formulation was measured. The formulations were also imaged by light microscopy and scanning electron microscopy. The absorptivity of oils was at least two orders of magnitude lower compared to the commercial UV blockers. The fruit juice powders were more effective at UV blocking but still showed an order of magnitude lower absorptivity compared to commercial UV blockers. The UV blocking from most natural oils is insufficient to obtain a significant UV protection. Formulations containing 50wt% purple carrot showed good UV-blocking capabilities and represent a promising ingredient for sunscreen and cosmetic applications. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  9. Ultrastructural changes of photodegradation of wood surfaces exposed to UV

    International Nuclear Information System (INIS)

    Kuo, M.L.; Hu, N.

    1991-01-01

    Red pine sapwood transverse and radial surfaces were exposed to ultraviolet (UV) light for 3 to 40 days. Effect of UV irradiation on ultrastructural changes of cell walls were studied by scanning (SEM) and transmission (TEM) electron microscopy. SEM study of transverse sections showed that during initial stages of UV irradiation, lignin in cell corners and in the compound middle lamellae was preferentially degraded and that the radial middle lamellae substained a greater rate of UV degradation than did the tangential middle lamellae. Massive cell wall degradation, as indicated by cell wall thinning, did not occur until surfaces were exposed to UV light for more than 10 days. TEM study of radial cell wall surfaces indicated that lignin lining the warty layer was removed by UV irradiation in 3 days and that warts were destroyed by a UV irradiation in 7 days. UV irradiation of cell wall surfaces produced a substantial amount of water-soluble degradation products. After 30 days of UV irradiation, the S3 layer was totally removed and revealed the very fragile S2 layer. (author)

  10. Stability of carotenoids toward UV-irradiation in hexane solution

    Directory of Open Access Journals (Sweden)

    DRAGAN CVETKOVIC

    2008-01-01

    Full Text Available The stabilities of four selected carotenoids dissolved in hexane, two carotenes and two xanthophylls, toward UV-irradiation of three different ranges (UV-A, UV-B and UV-C were studied in this work. The carotenoids underwent bleaching via a probable free radical mediated mechanism following first-order kinetics. The bleaching rates were highly dependent on the input of the involved photons and, although not consistently, on the chemical structures of the investigated compounds. For the two xanthophylls, a possible role of oxygen associated with their bleaching cannot be neglected.

  11. Environment Canada's Children's UV Index Sun Awareness Programme

    International Nuclear Information System (INIS)

    Fergusson, A.

    2000-01-01

    In 1992, Canada introduced the UV Index forecast programme to increase public awareness of UV radiation, to support health agencies in educating the public about UV risks, and to assist individuals in making healthy lifestyle decisions. A national sun health survey in 1997 indicated that about half of adults reported taking extra precautions to protect themselves from the sun on days when the UV Index was rated 'high'. In response to this concern in 1998, Environment Canada produced an UN Index poster that was sent to 3000 elementary schools across Canada. The poster targeted children between the ages of 8 and 15 and provided information to minimise the risk to their health from solar UV radiation without spoiling their outdoor fun. Based on this experience Environment Canada produced in 1999, the Daily UV Index and Calendar Poster that was sent to 14,000 elementary schools across Canada. An UV Index website has been created to provide information to students and teachers on the science of UV radiation and the UV Index. (author)

  12. Medical UV exposures and HIV activation

    International Nuclear Information System (INIS)

    Zmudzka, B.Z.; Miller, S.A.; Jacobs, M.E.; Beer, J.Z.

    1996-01-01

    This paper presents the first attempt to evaluate the potential of clinical UV exposures to induce the human immunodeficiency (HIV) promoter and, thus, to upregulate HIV growth in those skin cells that are directly affected by the exposure. Using the data for HIV promoter activation in vitro, we computed UVB and psoralen plus UVA (PUVA) doses that produce 50% of the maximal promoter activation (AD 50 ). Then, using (a) literature data for UV transmittance in the human skin, (b) a composite action spectrum for HIV promoter and pyrimidine dimer induction by UVB and (c) an action spectrum for DNA synthesis inhibition by PUVA, we estimated the distribution of medical UVB and PUVA doses in the skin. This allowed us to estimate how deep into the skin the HIV-activating doses might penetrate in an initial and an advanced stge of UVB and PUVA therapy. Such analysis was done for normal type II skin and for single exposures. For UVB we found that, when the incident dose on the surface of the skin is 500 J/m 2 (290-320 nm) (initial stage of the therapy), the dose producing 50% of the maximal HIV promoter activation (AD 50 UVB ) is limited to the stratum corneum. For PUVA we found that, when the incident UVA doses are 25 or 100 kJ/m 2 (320-400 nm) (an initial and an advanced stage of therapy, respectively), and the 8-methoxypsoralen concentration in the blood is 0.1 μg/mL (the desired level), the combined doses to the mid epidermis (and some areas of the upper dermis) are well below the 50% HIV promoter-activating PUVA dose (AD 50 PUVA ). These results suggest that the probability of HIV activation in the epidermis by direct mechanisms is higher for UVB than for PUVA treatment. However, complexities of the UV-inducible HIV activation and immunomodulatory phenomena are such that our results by themselves should not be taken as an indication that UVB therapy carries a high risk than PUVA therapy when administered to HIV-infected patients. (Author)

  13. Is UV-A radiation a cause of malignant melanoma. Er UV-A aarsak til malignt melanom

    Energy Technology Data Exchange (ETDEWEB)

    Moan, J. (Det Norske Radiumhospital, Oslo (Norway))

    1994-03-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs.

  14. Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

    Science.gov (United States)

    Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

    2014-06-01

    Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

  15. Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

    International Nuclear Information System (INIS)

    Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

    2014-01-01

    Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs. (invited article)

  16. Photodegradation and toxicity changes of antibiotics in UV and UV/H{sub 2}O{sub 2} process

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yuan [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Hu Chun, E-mail: huchun@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Xuexiang, Hu; Dongbin, Wei; Yong, Chen; Jiuhui, Qu [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2011-01-30

    The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H{sub 2}O{sub 2} process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H{sub 2}O{sub 2} process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R{sub OH,UV}, defined as the experimentally determined {center_dot}OH radical exposure per UV fluence. The R{sub OH,UV} values represent the background {center_dot}OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H{sub 2}O{sub 2} due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H{sub 2}O{sub 2} process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H{sub 2}O{sub 2} process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of {center_dot}OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H{sub 2}O{sub 2} process would be determined by parent compound degradation and toxicity changes.

  17. Electrically Injected UV-Visible Nanowire Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, George T.; Li, Changyi; Li, Qiming; Liu, Sheng; Wright, Jeremy Benjamin; Brener, Igal; Luk, Ting -Shan; Chow, Weng W.; Leung, Benjamin; Figiel, Jeffrey J.; Koleske, Daniel D.; Lu, Tzu-Ming

    2015-09-01

    There is strong interest in minimizing the volume of lasers to enable ultracompact, low-power, coherent light sources. Nanowires represent an ideal candidate for such nanolasers as stand-alone optical cavities and gain media, and optically pumped nanowire lasing has been demonstrated in several semiconductor systems. Electrically injected nanowire lasers are needed to realize actual working devices but have been elusive due to limitations of current methods to address the requirement for nanowire device heterostructures with high material quality, controlled doping and geometry, low optical loss, and efficient carrier injection. In this project we proposed to demonstrate electrically injected single nanowire lasers emitting in the important UV to visible wavelengths. Our approach to simultaneously address these challenges is based on high quality III-nitride nanowire device heterostructures with precisely controlled geometries and strong gain and mode confinement to minimize lasing thresholds, enabled by a unique top-down nanowire fabrication technique.

  18. Effects of UV radiation on genetic recombination

    International Nuclear Information System (INIS)

    Vlahovic, K.; Zahradka, D.; Petranovic, M.; Petranovic, D.

    1996-01-01

    We have used the model consisting of Escherichia coli cells and l phage to study the effects of UV radiation on genetic recombination. We found two radiation induced processes that reduce or inhibit genetic recombination. One such process leads to the inability of prophage to excise itself from the irradiated bacterial chromosome by the site-specific recombination. The other process was shown to inhibit a type of general recombination by which the prophage transfers one of its genetic markers to the infecting homologous phage. Loss of the prophage ability to take part in both site-specific and general recombination was shown to develop in recB + but not in recB cells. From this we infer that the loss of prophage recombinogenicity in irradiated cells is a consequence of one process in which RecBCD enzyme (the product of recB, recC and recD genes) plays an essential role. (author)

  19. Exposure to UV radiation and human health

    Science.gov (United States)

    Kimlin, Michael G.

    2005-08-01

    This paper will overview the significant issues facing researchers in relating the impact of exposure to sunlight and human health. Exposure to solar ultraviolet radiation is the major causative factor in most sun-related skin and eye disorders, however, very little is known quantitatively about human UV exposures. Interestingly, human exposure to sunlight also has a nutritional impact, namely the development of pre-Vitamin D, which is an important nutrient in bone health. New research suggest that low vitamin D status may be a causative factor in the development of selective types of cancer and autoimminue diseases, as well as a contributing factor in bone health. The 'health duality' aspect of sunlight exposure is an interesting and controversial topic that is a research focus of Kimlin's research group.

  20. Technical considerations during disinfection by UV

    International Nuclear Information System (INIS)

    Ekhtiarzadeh, Z.; Sadeghpur, H.

    2002-01-01

    The use of new methods for treatment of water and wastewater in the country is one the rise and therefore the theoretical and practical knowledge of the industry's engineers should increase simultaneously. Ultraviolet is one of the new technologies used both for treatment of water as well as wastewater. The UV disinfection system consists of different components such as the lamp, ballast and the lamp fixtures. Each has a specification, which should be taken into account prior to design, order and purchase. The subject of price is also among the important considerations. The article presents figures cost comparison in various sections. It does not try to either approve or reject other disinfection systems such as chlorination, but the writer believes that any method should find its own practice and conditions of use, and the disinfection system designers should opt for the best system suited to their plans and avoid limiting themselves to a single one

  1. Double transfer UV-curing nanoimprint lithography

    International Nuclear Information System (INIS)

    Shen, Yiming; Yao, Lei; Li, Zhiwei; Kou, Junlong; Cui, Yushuang; Bian, Jie; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng; Li, Wen-Di; Wu, Wei

    2013-01-01

    A challenge in the fabrication of nanostructures into non-planar substrates is to form a thin, uniform resist film on non-planar surfaces. This is critical to the fabrication of nanostructures via a lithographic technique due to the subsequent pattern transfer process. Here we report a new double transfer UV-curing nanoimprint technique that can create a nanopatterned thin film with a uniform residual layer not only on flat substrates but also on highly curved surfaces. Surface relief gratings with pitches down to 200 nm are successfully imprinted on the cylindrical surface of optical fibers, and further transferred into a SiO 2 matrix using reactive ion etching (RIE), demonstrating that our technique is applicable for fabricating high-resolution nanostructures on non-planar substrates. (paper)

  2. Protection policies for ionizing and UV radiation

    International Nuclear Information System (INIS)

    Bosnjakovic, B.F.M.

    1987-01-01

    Although ultraviolet radiation is generally considered as being part of non-ionizing radiation, the existing similarities with ionizing radiation are too striking to be overseen. A comparison of these two agents is becoming important in view of the increasing awareness of various environmental and health risks and the tendency to develop more uniform risk management policies with respect to the different physical and chemical agents. This paper explores the similarities and differences of UV and ionizing radiation from the point of view of policies either adopted or in development. Policy determinants include, among others, the following factors: biological effects, dosimetric quantities, relative contribution to exposure from different sources, hazard potential of different sources, quantification of detrimental consequences, public perception of the radiation hazards and regulation developments. These factors are discussed

  3. Water and UV degradable lactic acid polymers

    Science.gov (United States)

    Bonsignore, P.V.; Coleman, R.D.

    1996-10-08

    A water and UV light degradable copolymer is described made from monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  4. Recent studies on UV radiation in Brazil

    Science.gov (United States)

    Correa, M. P.; Ceballos, J. C.; Moregula, A.; Okuno, E.; Fausto, A.; Mol, A.; Santos, J. C.

    2009-04-01

    This presentation shows a summary of UV index measurements performed in the last years in Southeastern (SE) and Northeastern (NE) Brazilian regions. Brazil has an area of 8.5 million km2 distributed between latitudes 5˚ N and 35˚ S and longitudes 5˚ W and 75˚ W. SE is the most important economic pole of South America and the NE coast is an important tourist region. This large area has a great diversity of climatic, atmospheric and geographical conditions in addition to very diverse social and cultural habits. Non-melanoma skin cancer (NMSC) is an epidemiological health problem with more than 120,000 new cases each year. The most of these cases are found in the South and Southeast regions, with about 70 new NMSC per 100,000 inhabitants. Solar Light UV501 biometers are installed in the SE cities of São Paulo (23.6˚ S, 46.7˚ W, 865 m ASL), Itajubá/Minas Gerais (22.4˚ S; 45.5˚ W, 846 m ASL) and the NE city of Ilhéus/Bahia (14.8˚ S; 39.3˚ W; 54 m ASL). First measurements began in 2005 in São Paulo city, while Itajubá and Ilhéus have regular measurements from the beginning of 2008. Other studies related to the UV radiation modeling and interactions with atmosphere components, as ozone, aerosols and clouds, have also been performed. For example: a) UVI modelling calculations performed by a multiple-scattering spectral models; b) studies on the aerosol radiative properties based on satellite (MODIS/Terra-Aqua) and ground-based (Aeronet) observation; c) ozone content variability from satellite (OMI/Aura) and ground-based (Microtops ozonometer) measurements; d) behavioral profile of the population, as regarding habits of solar exposure and sun protection measures. Results show that more than 75% of the measurements conducted in the summer (outside noon) can be classified as upper than high UVI according to World Health Organization (WHO) recommended categories: Low (UVI UV radiation levels to have a population very exposed during its

  5. Simulation and comparative study on the oxidation kinetics of atrazine by UV/H₂O₂, UV/HSO₅⁻ and UV/S₂O₈²⁻.

    Science.gov (United States)

    Luo, Congwei; Ma, Jun; Jiang, Jin; Liu, Yongze; Song, Yang; Yang, Yi; Guan, Yinghong; Wu, Daoji

    2015-09-01

    This study comparatively investigated atrazine (ATZ) degradation by irradiation at the wavelength of 254 nm in the presence of peroxides including hydrogen peroxide (H2O2), peroxymonosulfate (HSO5(-)), and persulfate (S2O8(2-)) at various initial ATZ concentrations and oxidant dosages. The effects of water matrix, such as carbonate/bicarbonate (HCO3(-)/CO3(2-)), chloride ions (Cl(-)), and natural organic matter (NOM), were evaluated on these three advanced oxidation processes. A simple steady-state kinetic model was developed based on the initial rates of ATZ destruction, which could well describe the apparent pseudo-first-order rate constants (k(app), s(-1)) of ATZ degradation in these three processes. The specific roles of reactive species (i.e., HO·, SO4(-·), CO3(-·), and Cl2(-·)) under various experimental conditions were quantitatively evaluated based on their steady-state concentrations obtained from this model. Modeling results showed that the steady-state concentrations of HO· and SO4(-·) decreased with the increase of CO3(2-)/HCO3(-) concentration, and the relative contribution of HO· to ATZ degradation significantly decreased in UV/H2O2 and UV/HSO5(-) systems. On the other hand, the scavenging effect of HCO3(-)/CO3(2-) on the relative contribution of SO4(-·) to ATZ degradation was lower than that on HO·. The presence of Cl(-) (0.5-10 mM) significantly scavenged SO4(-·) but had slightly scavenging effect on HO· at the present experimental pH, resulting in greater decrease of k(app) in the UV/S2O8(2-) than UV/H2O2 and UV/HSO5(-) systems. Higher levels of Cl2(-·) were generated in the UV/S2O8(2-) than those in the UV/H2O2 and UV/HSO5(-) systems at the same Cl(-) concentrations. NOM significantly decreased k(app) due to its effects of competitive UV absorption and radical scavenging with the latter one being dominant. These results improve the understanding of the effects of water constituents for ATZ degradation in the UV-based oxidation

  6. Quality assurance of the UV irradiances of the UV-B Monitoring and Research Program: the Mauna Loa test case

    Science.gov (United States)

    Zempila, Melina Maria; Davis, John; Janson, George; Olson, Becky; Chen, Maosi; Durham, Bill; Simpson, Scott; Straube, Jonathan; Sun, Zhibin; Gao, Wei

    2017-09-01

    The USDA UV-B Monitoring and Research Program (UVMRP) is an ongoing effort aiming to establish a valuable, longstanding database of ground-based ultraviolet (UV) solar radiation measurements over the US. Furthermore, the program aims to achieve a better understanding of UV variations through time, and develop a UV climatology for the Northern American section. By providing high quality radiometric measurements of UV solar radiation, UVMRP is also focusing on advancing science for agricultural, forest, and range systems in order to mitigate climate impacts. Within these foci, the goal of the present study is to investigate, analyze, and validate the accuracy of the measurements of the UV multi-filter rotating shadowband radiometer (UV-MFRSR) and Yankee (YES) UVB-1 sensor at the high altitude, pristine site at Mauna Loa, Hawaii. The response-weighted irradiances at 7 UV channels of the UV-MFRSR along with the erythemal dose rates from the UVB-1 radiometer are discussed, and evaluated for the period 2006-2015. Uncertainties during the calibration procedures are also analyzed, while collocated groundbased measurements from a Brewer spectrophotometer along with model simulations are used as a baseline for the validation of the data. Besides this quantitative research, the limitations and merits of the existing UVMRP methods are considered and further improvements are introduced.

  7. Light Conversion and Scattering in UV Protective Textiles

    Directory of Open Access Journals (Sweden)

    Grancarić Ana Marija

    2014-12-01

    Full Text Available The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80% of UV-R gets absorbed, whilst in the remaining 20% gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA, UV-B protective agents, as well as nanoparticles, if applied. Based on electronically excited state by energy of UV-R (usually 340-370 nm, the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, is very resistant to washing and improves the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene-derived FWAs were applied on cotton fabric in wide concentration

  8. Expression of Nudix hydrolase genes in barley under UV irradiation

    Science.gov (United States)

    Tanaka, Sayuri; Sugimoto, Manabu; Kihara, Makoto

    Seed storage and cultivation should be necessary to self-supply foods when astronauts would stay and investigate during long-term space travel and habitation in the bases on the Moon and Mars. Thought the sunlight is the most importance to plants, both as the ultimate energy source and as an environmental signal regulating growth and development, UV presenting the sunlight can damage many aspects of plant processes at the physiological and DNA level. Especially UV-C, which is eliminated by the stratospheric ozone layer, is suspected to be extremely harmful and give a deadly injury to plants in space. However, the defense mechanism against UV-C irradiation damage in plant cells has not been clear. In this study, we investigated the expression of Nudix hydrolases, which defense plants from biotic / abiotic stress, in barley under UV irradiation. The genes encoding the amino acid sequences, which show homology to those of 28 kinds of Nudix hydrolases in Arabidopsis thaliana, were identified in the barley full-length cDNA library. BLAST analysis showed 14 kinds of barley genes (HvNUDX1-14), which encode the Nudix motif sequence. A phylogenetic tree showed that HvNUDX1, HvNUDX7, HvNUDX9 and HvNUDX11 belonged to the ADP-ribose pyrophosphohydrolase, ADP-sugar pyrophosphohydrolase, NAD(P)H pyrophosphohydrolase and FAD pyrophosphohydrolase subfamilies, respectively, HvNUDX3, HvNUDX6, and HvNUDX8 belonged to the Ap _{n}A pyrophosphohydrolase subfamilies, HvNUDX5 and HvNUDX14 belonged to the coenzyme A pyrophosphohydrolase subfamilies, HvNUDX12 and HvNUDX13 belonged to the Ap _{4}A pyrophosphohydrolase subfamilies. Induction of HvNUDX genes by UV-A (340nm), UV-B (312nm), and UV-C (260nm) were analyzed by quantitative RT-PCR. The results showed that HvNUDX4 was induced by UV-A and UV-B, HvNUDX6 was induced by UV-B and UV-C, and HvNUDX7 and HvNUDX14 were induced by UV-C, significantly. Our results suggest that the response of HvNUDXs to UV irradiation is different by UV

  9. UV “Indices”—What Do They Indicate?

    Directory of Open Access Journals (Sweden)

    Hanns Moshammer

    2016-10-01

    Full Text Available Ultra-Violet (UV radiation covers the spectrum of wavelengths from 100 to 400 nm. The potency and biological activity for a variety of endpoints differ by wavelength. For monitoring and communication purposes, different UV action spectra have been developed. These spectra use different weighting functions. The action spectrum for erythemal dose is the most widely used one. This erythemal dose per time or dose-rate has been further simplified into a “UV index”. Following this example, in our review we use the term “index” or (plural “indices” in a more general description for all simplified single-value measures for any biologically effective UV dose, e.g., for human non-melanoma skin cancer and for previtamin D production rate. Ongoing discussion about the existence of an increased melanoma risk due to UV-A exposure underscores the uncertainties inherent in current weighting functions. Thus, we performed an online literature search to review the data basis for these indices, to understand their relevance for an individual, and to assess the applicability of the indices for a range of exposure scenarios. Even for natural (solar UV, the spectral composition varies spatially and temporally. Artificial UV sources and personal protection introduce further variation to the spectral composition. Many biological effects are proposed for UV radiation. Only few endpoints have been studied sufficiently to estimate a reliable index. Weighting functions for chronic effects and most importantly for cancer endpoints have been developed in animal models, and often for proxy endpoints only. Epidemiological studies on biological effects of UV radiation should not only depend on single-value weighted UV dose estimates (indexes but should strive for a more detailed description of the individual exposure. A better understanding of the adverse and beneficial effects of UV radiation by wavelength would also improve medical counseling and health

  10. UV ability to destroy poliovirus end FRNA specific bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J.; Joret, J.C.; Lesavre, J.; Perrot, J.Y.

    1996-01-01

    In France, the use of ultraviolet radiation to disinfect secondary effluents is only in its initial stage. The aim of this study was to examine the ability of UV to destroy Poliovirus Type 1 and FRNA specific bacteriophages (laboratory MS2 phages and indigenous phages). Concentrated viral solutions were mixed with secondary effluents artificially enriched with suspended solids and then irradiated at various UV dose in a collimated beam. Bacteriological analysis of Escherichia coli and enterococci were performed at the same time. UV were very efficient to kill Poliovirus : Inactivation of 3 and 5 log units were observed respectively at UV doses of 20 and 40 mW/cm{sup 2}. The Poliovirus disinfection rate was almost the same than Escherichia coli. Enterococci were more resistant than E. coli. Inactivation of MS2 bacteriophages was significantly correlated to UV dose following the relationship MS2 Inactivation = 0.047{sup *} Dose + 0,396. At UV dose of 20 mWs/cm{sup 2}, MS2 phages were 2.3 times more resistant to UV than Poliovirus, i.e. they need UV dose 2,3 times greater to be disinfected at the same level. A review of the literature has also shown that viruses more resistant to UV treatment have never been reported. All this would tend to confirm the interest of this group of virus as indicators of the disinfection efficiency of UV, which could indicate, on site, the inactivation of pathogenic viruses. Inactivation rates obtained for FRNA phages proved the good virucidal activity of UV. The inactivation of indigenous FRNA bacteriophages was not correlated with E. coli inactivation. On the other hand, it was correlated with enterococci inactivation. (Author). 23 refs., 7 figs., 4 tabs.

  11. Improved Techniques for Low-Flux Measurement of Prompt Neutron Lifetime, Conversion Ratio and Fast Spectra; Methodes Perfectionnees de Mesure de la Duree de Vie des Neutrons Instantanes, du Rapport de Conversion et des Spectres de Neutrons Rapides, dans un Reacteur a Bas Flux; Usovershenstvovannye metody izmereniya vremeni zhizni mgnovennykh nejtronov, koehffitsienta konversii i spektra bystrykh nejtronov pri slabykh potokakh nejtronov; Tecnicas Perfeccionadas para la Determinacion del Periodo de los Neutrones Inmediatos, la Razon de Conversion y los Espectros de Neutrones Rapidos, con Flujos Reducidos

    Energy Technology Data Exchange (ETDEWEB)

    Armani, R. J.; Bennett, E. F.; Brenner, M. W.; Bretscher, M. M.; Cohn, C. E.; Huber, R. J.; Kaufmann, S. G.; Redman, W. C. [Argonne National Laboratory, Argonne, IL (United States)

    1964-02-15

    feuilles d'enrichissements differents pour etablir la contribution des fissions dans la matiere fertile a l'activite des produits de fission et des feuilles exposees a differents'spectres pour distinguer les coups dus a des fissions dans la determination des captures; emploi du comptage par coiencidence pour la detection de la decroissance de {sup 239}Np. Pour obtenir une valeur exprimant le rapport de conversion, a partir des donnees relatives a l'activation, il faut connaitre le rapport entre les captures et les fissions dans le combustible. Il n'existe pas a l'heure actuelle de methodes experimentales precises pour mesurer ce rapport dans un reacteur a bas flux; plusieurs methodes qui pourraient etre utilisees a cette fin sont en cours d'etude. Les auteurs decrivent trois des methodes qui offrent les perspectives les plus favorables. Pour construire un petit spectrometre a neutrons rapides, ayant une bonne stabilite, un bon pouvoir de resolution et une bonne sensibilite en vue de la mesure en pile des spectres neutroniques compris dans la gamme d'energies des dizaines et des centaines de kV, les auteurs ont concentre leurs efforts sur l'utilisation de l'analyse de la forme des impulsions - afin d'eliminer les evenements produits par les rayons gamma dans les compteurs proportionnels fondes sur des protons de recul de l'hydrogene - et sur l'introduction de la collimation dans les 'sandwiches' {sup 6}LiF-semi-conducteurs - afin d'augmenter le pouvoir de resolution. Ils ont construit un certain nombre de ces appareils et etudie leur reponse aux neutrons monocinetiques et aux neutrons produits dans un reacteur. En utilisant la technique d'elimination des rayons gamma, ils ont pu reduire de plusieurs centaines de fois la sensibilite du compteur de recul aux rayons gamma et de cette maniere abaisser la limite inferieure d'application de l'instrument a 30 keV. Pour les appareils {sup 6}Li-semi-conducteurs, ils ont observe des pouvoirs de resolution de 70 keV ( largeur entiere

  12. Solar UV exposure among outdoor workers in Denmark measured with personal UV-B dosimeters

    DEFF Research Database (Denmark)

    Grandahl, Kasper; Mortensen, Ole Steen; Sherman, David Zim

    2017-01-01

    radiation exposure are needed to help resolve this problem. This can be done using personal ultraviolet radiation dosimeters. Methods: We consider technical and practical feasibility of measuring individual solar ultraviolet exposure at work and leisure in professions with different á priori temporal high......-level outdoor worktime, using aluminium gallium nitride (AlGaN) photodiode detector based personal UV-B dosimeters. Essential technical specifications including the spectral and angular responsivity of the dosimeters are described and pre-campaign dosimeter calibration applicability is verified. The scale...... with our specialist knowledge as occupational physicians. Conclusions: Large-scale use of personal UV-B dosimeters for measurement of solar ultraviolet radiation exposure at work and leisure in Denmark is indeed feasible from a technical and practical viewpoint. Samples of exposure data shown support...

  13. Presence of UV-endonuclease sensitive sites in daughter DNA of UV-irradiated mammalian cells

    International Nuclear Information System (INIS)

    D'Ambrosio, S.; Setlow, R.B.

    1978-02-01

    Asynchronous Chinese hamster cells were irradiated with 10 Jm -2 uv radiation and 0.25 to 4 hours later pulse-labeled with [ 3 H]thymidine. Cells synchronized by shaking off mitotic and G 1 cells were irradiated in either the G 1 -phase or S-phase of the cell cycle and pulse-labeled with [ 3 H]thymidine in the S-phase. After a 12 to 14 hour chase in unlabeled medium, the DNA was extracted, incubated with Micrococcus luteus uv-endonuclease and sedimented in alkaline sucrose. The number of endonuclease sensitive sites decreased as the time between uv irradiation and pulse-labeling of daughter DNA increased. Further, there were significantly less endonuclease sensitive sites in the daughter DNA from cells irradiated in the G 1 -phase than in the S-phase. These data indicate that very few, if any, dimers are transferred from parental DNA to daughter DNA and that the dimers detected in daughter DNA may be due to the irradiation of replicating daughter DNA before labeling

  14. Monitoring and control of UV and UV-TiO{sub 2} disinfections for municipal wastewater reclamation using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chuang-Hung [Department of Architecture, National United University, Miao-Li 360, Taiwan, ROC (China); Yu, Ruey-Fang, E-mail: rfyu@nuu.edu.tw [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China); Cheng, Wen-Po; Liu, Chun-Ru [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer ANN models can effectively control both UV and UV-TiO{sub 2} disinfections for wastewater reuse. Black-Right-Pointing-Pointer Comparing to UV disinfection, UV-TiO{sub 2} disinfection can save 13.2-15.7% of UV dosage and capacity. Black-Right-Pointing-Pointer SS decreases disinfection efficiency when UV doses were <10,000 {mu}W s/cm{sup 2}. - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO{sub 2} can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO{sub 2} disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO{sub 2} disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO{sub 2} disinfections. A novel ANN control strategy is applied to control UV and UV-TiO{sub 2} disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO{sub 2} disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO{sub 2} disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2-15.7%.

  15. Risks of increased UV-B radiation for humans

    International Nuclear Information System (INIS)

    Przybilla, B.; Eberlein-Koenig, B.; Bergner, T.

    1994-01-01

    If not compensated in any way, depletion of the stratospheric ozone layer leads to an increase of UV-B radiation at the earth's surface, especially towards the short-wave range, which is biologically the more active. The most concerning effect here is that of UV-B induced skin reactions, in particular malignant skintumors (malignant melanoma, spinocellular carcinoma, basalioma), whose incidence is expected to increase in future. As some photoreactions can be inhibited or enhanced also by radiation outside their action spectrum, it is possible for changes in solar spectral radiation flux density to influence photo-induced reactions that are driven at wavelengths outside the UV-B range. The authors have performed studies for developing methods of quantifying individual UV sensitivity. In vitro studies have shown that UV-A dependent photoreactions can be partly inhibited by UV-B. A number of drugs, as well as sulphites, which are used as preservatives amongst other things, have been shown to have phototoxic properties that may be relevant to photocarcinogenesis. Irradiation tests on cell cultures for different UV-B ranges have shown that irradiation at shorter wavelengths leads to a stronger release of proinflammatory cytokines that ar longer wavelengths with the same dose. Altogether it can be said that despite compelling theoretical evidence it is not easily possible to predict the actual consequences of an increase in particular of short-wave UV-B radiation at the earth's surface. The assumed effects must be examined individually by appropriate methods. (orig.) [de

  16. Symmetrical waveguide devices fabricated by direct UV writing

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz; Svalgaard, Mikael

    2002-01-01

    Power splitters and directional couplers fabricated by direct UV writing in index matched silica-on-silicon samples can suffer from an asymmetrical device performance, even though the UV writing is carried out in a symmetrical fashion. This effect originates from a reduced photosensitivity...

  17. Formation and removal of genotoxic activity during UV/H

    NARCIS (Netherlands)

    Heringa, M.B.; Harmsen, D.J.H.; Beerendonk, E.F.; Reus, A.A.; Krul, C.A.M.; Metz, D.H.; Ijpelaar, G.F.

    2011-01-01

    The objective of this study was to determine the genotoxic activity of water after UV/H2O2 oxidation and GAC filtration. Pre-treated surface water from three locations was treated with UV/H2O2 with medium pressure (MP) lamps and passed through granulated

  18. UV astronomy throughout the ages: a historical perspective

    Science.gov (United States)

    Linsky, Jeffrey L.

    2018-05-01

    Astronomers have long recognized the critical need for ultraviolet imaging, photometry and spectroscopy of stars, planets, and galaxies, but this need could not be satisfied without access to space and the development of efficient instrumentation. When UV measurements became feasible, first with rockets and then with satellites, major discoveries came rapidly. It is true in the UV spectral region as in all others, that significant increases in sensitivity, spectral resolution, and time domain coverage have led to significant new understanding of astrophysical phenomena. I will describe a selection of these discoveries made in each of three eras: (1) the early history of rocket instrumentation and Copernicus, the first UV satellite, (2) the discovery phase pioneered by the IUE, FUSE and EUVE satellites, and (3) the full flowering of UV astronomy with the successful operation of HST and its many instruments. I will also mention a few areas where future UV instrumentation could lead to new discoveries. This review concentrates on developments in stellar and interstellar UV spectroscopy; the major discoveries in galactic, extragalactic, and solar system research are beyond the scope of this review. The important topic of UV technologies and detectors, which enable the remarkable advances in UV astronomy are also not included in this review.

  19. UV curing by radical, cationic and concurrent radicalcationic polymerization

    International Nuclear Information System (INIS)

    Pappas, S.P.

    1984-01-01

    UV and EB curing represent complementary technologies with respective advantages and disadvantages. This paper deals with the design and evaluation of UV curable coatings to optimize cure rate and film properties. Topics included are state-of-the-art photoinitiator systems, light intensity effects, retardation of air-inhibition, adhesion, and amplification of photons for enhanced speed of cure

  20. UV patterned nanoporous solid-liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Sagar, Kaushal Shashikant; Christiansen, Mads Brøkner

    2010-01-01

    Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (delta n = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part...

  1. UV ACTIVATION OF RECEPTOR TYROSINE KINASE-ACTIVITY

    NARCIS (Netherlands)

    COFFER, PJ; BURGERING, BMT; PEPPELENBOSCH, MP; BOS, JL; KRUIJER, W

    1995-01-01

    The exposure of mammalian cells to ultraviolet radiation (UV) may lead to DNA damage resulting in mutation and thus possibly cancer, while irradiation can further act as a potent tumour promoter. In addition UV induces p21ras-mediated signalling leading to activation of transcription factors such as

  2. Postirradiation properties of a UV-sensitive variant of CHO

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.D.; de Veciana, M.; Presson-Tincknell, B. (California Univ., Berkeley (USA). Lawrence Berkeley Lab.)

    1982-08-01

    A UV-hypersensitive mutant of Chinese hamster ovary (CHO) cells, termed 43-3B, has been used in a comparative study with the wild type CHO in order to determine the involvement of repair in several postirradiation phenomena. 43-3B has the same growth rate and chromosome number as the wild type CHO-9. It is hypersensitive to UV irradiation. 43-3B shows only about 17% of the UV-stimulated unscheduled DNA repair synthesis of CHO-9 as measured by autoradiography. When breaks in supercoiled chromatin are measured after UV by the nucleoid sedimentation method, the mutant appears to be capable of carrying out only limited incision. A much reduced ability to recover control rates of semiconservative DNA synthesis after UV irradiation was observed in the repair-deficient 43-3B cell line, suggesting that the removal of UV-induced replication blocks by excision repair is the most important factor in allowing recovery of UV-inhibited DNA synthesis. Recovery of colony-forming ability between fractionated UV exposures was observed in the wild type CHO-9, but little recovery was seen in 43-3B. This indicates that excision repair capability can also be important in split-fluence recovery.

  3. Covalent bindings in proteins following UV-C irradiation

    International Nuclear Information System (INIS)

    Diezel, W.; Meffert, H.; Soennichsen, N.; Reinicke, C.

    1980-01-01

    Following a UV-C irradiation of catalase cross-linked catalase subunits could be detected by sodium dodecylsulfate gel electrophoresis. The subunits of aldolase were not cross-linked. The origin of covalent bindings in the catalase molecule is suggested to be effected by a free radical chain reaction induced by the heme component of catalase after UV-C irradiation. (author)

  4. Preparation of temperature responsive fragrance release membranes by UV curing

    International Nuclear Information System (INIS)

    Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao; Okuda, Jyunya; Kitami, Toshiaki; Matsubara, Yoshio

    2003-01-01

    The authors have studied the preparation and the function of intelligent drug release membranes by UV curing. Temperature responsive fragrance release membranes were prepared by UV curing process and the release functions were investigated as the function of thickness and composition of membrane. Microscopic observations were used to prove the postulated release mechanism

  5. Formation dynamics of UV and EUV induced hydrogen plasma

    NARCIS (Netherlands)

    Dolgov, A.A.; Lee, Christopher James; Yakushev, O.; Lopaev, D.V.; Abrikosov, A.; Krivtsun, V.M.; Zotovich, A.; Bijkerk, F.

    2014-01-01

    The comparative study of the dynamics of ultraviolet (UV) and extreme ultraviolet (EUV) induced hydrogen plasma was performed. It was shown that for low H2 pressures and bias voltages, the dynamics of the two plasmas are significantly different. In the case of UV radiation, the plasma above the

  6. Interaction of UV laser pulses with reactive dusty plasmas

    NARCIS (Netherlands)

    van de Wetering, F.M.J.H.; Beckers, J.; Nijdam, S.; Oosterbeek, W.; Kovacevic, E.; Berndt, J.

    2016-01-01

    This contribution deals with the effects of UV photons on the synthesis and transport of nanoparticles in reactive complex plasmas (capacitively coupled RF discharge). First measurements showed that the irradiation of a reactive acetylene-argon plasma with high-energy, ns UV laser pulses (355 nm, 75

  7. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...

  8. Climate Variability, Dissolved Organic Carbon, UV Exposure, and Amphibian Decline

    Science.gov (United States)

    Brooks, P. D.; O'Reilly, C. M.; Diamond, S.; Corn, S.; Muths, E.; Tonnessen, K.; Campbell, D. H.

    2001-12-01

    Increasing levels of UV radiation represent a potential threat to aquatic organisms in a wide range of environments, yet controls on in situ variability on UV exposure are relatively unknown. The primary control on the penetration of UV radiation in surface water environments is the amount of photoreactive dissolved organic carbon (DOC). Consequently, biogeochemical processes that control the cycling of DOC also affect the exposure of aquatic organisms to UV radiation. Three years of monitoring UV extinction and DOC composition in Rocky Mountain, Glacier, Sequoia/ Kings Canyon, and Olympic National Parks demonstrate that the amount of fulvic acid DOC is much more important than the total DOC pool in controlling UV attenuation. This photoreactive component of DOC originates primarily in soil, and is subject both to biogeochemical controls (e.g. temperature, moisture, vegetation, soil type) on production, and hydrologic controls on transport to surface water and consequently UV exposure to aquatic organisms. Both of these controls are positively related to precipitation with greater production and transport associated with higher precipitation amounts. For example, an approximately 20 percent reduction in precipitation from 1999 to 2000 resulted in a 27% - 59% reduction in the amount of photoreactive DOC at three sites in Rocky Mountain National Park. These differences in the amount of hydrophobic DOC result in an increase in UV exposure in the aquatic environment by a factor of 2 or more. Implications of these findings for observed patterns of amphibian decline will be discussed.

  9. UV-B Radiation Contributes to Amphibian Population Declines

    Science.gov (United States)

    Blaustein, Andrew

    2007-05-01

    UV-B (280-315 nm) radiation is the most significant biologically damaging radiation at the terrestrial surface. At the organismal level, UV-B radiation can slow growth rates, cause immune dysfunction and result in sublethal damage. UV-B radiation can lead to mutations and cell death. Over evolutionary time, UV radiation has been an important stressor on living organisms. Natural events, including impacts from comets and asteroids, volcanic activity, supernova explosions and solar flares, can cause large-scale ozone depletion with accompanying increases in UV radiation. However, these natural events are transient. Moreover, the amount of ozone damage due to natural events depends upon a number of variables, including the magnitude of the event. This is different from modern-day human-induced production of chlorofluorocarbons (CFCs) and other chemicals that deplete stratospheric ozone continuously, resulting in long-term increases in UV-B radiation at the surface of the earth. We will briefly review the effects of UV-B exposure in one group of aquatic organisms_amphibians. UV-B has been implicated as a possible factor contributing to global declines and range reductions in amphibian populations.

  10. Plasmid mediated enhancement of uv resistance in Streptococcus faecalis

    International Nuclear Information System (INIS)

    Miehl, R.; Miller, M.; Yasbin, R.E.

    1980-01-01

    A 38.5-Mdal plasmid of Streptococcus faecalis subdp. zymogenes has been shown to enhance survival following uv irradiation. In addition, the presence of this plasmid increases the mutation frequencies following uv irradiation and enhanced W-reactivation. The data presented indicate that S. faecalis has an inducible error-prone repair system and that the plasmid enhances these repair functions

  11. Effect of uv irradiation on lambda DNA transcription

    Energy Technology Data Exchange (ETDEWEB)

    Ranade, S S [Cancer Research Inst., Bombay (India)

    1977-05-01

    The effect of uv irradiation of template DNA has been studied in vitro in the E.coli RNA polymerase system with native and uv treated lambda DNA. Lambda DNA was more susceptible to uv than was calf-thymus DNA, yet a residual activity was observed at a uv dose of 0.5 x 10/sup 4/ erg/mm/sup 2/. From the kinetic analysis of the reaction and the incorporation of lambda /sup 32/P-labelled nucleoside triphosphates, it seems reasonable to conclude that uv irradiation probably did not affect the DNA initiation sites, recognizable by RNA polymerase. The transcription products made with uv irradiated lambda DNA were asymmetrical, and hybridized to the right half (R) and the left half (L) of lambda DNA with the ratio of R/L=4/1, and they showed a lower hybridizability than the transcripts with native lambda DNA. The initiation sites recognizable by RNA polymerase seemed to be the same on both native and uv irradiated lambda DNA, though the transcription of uv treated lambda DNA appeared to terminate with rather short RNA chains.

  12. Effects of UV irradiation and UV/chlorine co-exposure on natural organic matter in water

    International Nuclear Information System (INIS)

    Liu, Wei; Zhang, Zaili; Yang, Xin; Xu, Yiyue; Liang, Yongmei

    2012-01-01

    The effects of co-exposure to ultraviolet (UV) irradiation (with either low- or medium-pressure UV lamps) and free chlorine (chloramine) at practical relevant conditions on changes in natural organic matter (NOM) properties were investigated using four waters. The changes were characterized using the specific disinfection by-product formation potential (SDBPFP), specific total organic halogen formation potential (STOXFP), differential UV absorbance (∆UVA), and size-exclusion chromatography (SEC). The results for exposure to UV irradiation alone and for samples with no exposure were also obtained. The SDBPFPs in all UV-irradiated NOM waters observed were higher than those of non-irradiated samples. UV irradiation led to increases in STOXFPs as a result of chlorination, but no changes, or only small decreases, from chloramination. UV irradiation alone led to positive ∆UVA spectra of the four NOM waters; co-exposure to UV and chlorine gave larger negative ∆UVA spectra than those obtained by chlorine exposure alone. No obvious changes in SEC results were observed for samples only irradiated with UV light; co-exposure gave no detectable changes in the abundances of small fractions for exposure to chlorine only. Both UV photooxidation and photocatalytic oxidation appear to affect the reactivity of the NOM toward subsequent chlorination, and the magnitude of the changes is generally greater for medium-pressure lamps than for low-pressure lamps. These results suggest that applying UV disinfection technology to a particular source may not always be disinfection by-product-problem-free, and the interactions between UV light, chlorine, and NOM may need to be considered. - Highlights: ► We discussed the effects of co-exposure to UV light and chlorine on properties of natural organic matters in waters. ► UV irradiation led to increases in SDBPFP and STOXFP of NOM waters from chlorination. ► We suggest that applying an UV disinfection technology to a particular

  13. Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S).

    Science.gov (United States)

    Hopf, Nancy B; Spring, Philipp; Hirt-Burri, Nathalie; Jimenez, Silvia; Sutter, Benjamin; Vernez, David; Berthet, Aurelie

    2018-05-01

    Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm 2 /h) compared to without (0.02-0.26 ng/cm 2 /h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm 2 /h) compared to with UV-S (0.40-6.35 ng/cm 2 /h). Time until permeation (T lags ) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Comparison of UV-LED and low pressure UV for water disinfection: Photoreactivation and dark repair of Escherichia coli.

    Science.gov (United States)

    Li, Guo-Qiang; Wang, Wen-Long; Huo, Zheng-Yang; Lu, Yun; Hu, Hong-Ying

    2017-12-01

    Studies on ultraviolet light-emitting diode (UV-LED) water disinfection have shown advantages, such as safety, flexible design, and lower starting voltages. However, information about reactivation after UV-LED disinfection is limited, which is an important issue of UV light-based technology. In this study, the photoreactivation and dark repair of Escherichia coli after UV-LEDs and low pressure (LP) UV disinfection were compared. Four UV-LED units, 265 nm, 280 nm, the combination of 265 + 280 (50%), and 265 + 280 (75%) were tested. 265 nm LEDs was more effective than 280 nm LEDs and LP UV lamps for E. coli inactivation. No synergic effect for disinfection was observed from the combination of 265 and 280 nm LEDs. 265 nm LEDs had no different reactivation performances with that of LP UV, while 280 nm LEDs could significantly repress photoreactivation and dark repair at a low irradiation intensity of 6.9 mJ/cm 2 . Furthermore, the UV-induced damage of 280 nm LEDs was less repaired which was determined by endonuclease sensitive site (ESS) assay. The impaired protein activities by 280 nm LEDs might be one of the reasons that inhibited reactivation. A new reactivation rate constant, K max , was introduced into the logistic model to simulate the reactivation data, which showed positive relationship with the maximum survival ratio and was more reasonable to interpret the results of photoreactivation and dark repair. This study revealed the distinct roles of different UV lights in disinfection and reactivation, which is helpful for the future design of UV-LED equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Degradation of sulfamethoxazole by UV, UV/H2O2 and UV/persulfate (PDS): Formation of oxidation products and effect of bicarbonate.

    Science.gov (United States)

    Yang, Yi; Lu, Xinglin; Jiang, Jin; Ma, Jun; Liu, Guanqi; Cao, Ying; Liu, Weili; Li, Juan; Pang, Suyan; Kong, Xiujuan; Luo, Congwei

    2017-07-01

    The frequent detection of sulfamethoxazole (SMX) in wastewater and surface waters gives rise of concerns about their ecotoxicological effects and potential risks to induce antibacterial resistant genes. UV/hydrogen peroxide (UV/H 2 O 2 ) and UV/persulfate (UV/PDS) advanced oxidation processes have been demonstrated to be effective for the elimination of SMX, but there is still a need for a deeper understanding of product formations. In this study, we identified and compared the transformation products of SMX in UV, UV/H 2 O 2 and UV/PDS processes. Because of the electrophilic nature of SO 4 - , the second-order rate constant for the reaction of sulfate radical (SO 4 - ) with the anionic form of SMX was higher than that with the neutral form, while hydroxyl radical (OH) exhibited comparable reactivity to both forms. The direct photolysis of SMX predominately occurred through cleavage of the NS bond, rearrangement of the isoxazole ring, and hydroxylation mechanisms. Hydroxylation was the dominant pathway for the reaction of OH with SMX. SO 4 - favored attack on NH 2 group of SMX to generate a nitro derivative and dimeric products. The presence of bicarbonate in UV/H 2 O 2 inhibited the formation of hydroxylated products, but promoted the formation of the nitro derivative and the dimeric products. In UV/PDS, bicarbonate increased the formation of the nitro derivative and the dimeric products, but decreased the formation of the hydroxylated dimeric products. The different effect of bicarbonate on transformation products in UV/H 2 O 2 vs. UV/PDS suggested that carbonate radical (CO 3 - ) oxidized SMX through the electron transfer mechanism similar to SO 4 - but with less oxidation capacity. Additionally, SO 4 - and CO 3 - exhibited higher reactivity to the oxazole ring than the isoxazole ring of SMX. Ecotoxicity of transformation products was estimated by ECOSAR program based on the quantitative structure-activity relationship analysis as well as by experiments using

  16. Description d'un nouveau brûleur compact. Fonctionnement en régime de gaz prémélangés Description of a New Compact Premixed Gas Burner

    Directory of Open Access Journals (Sweden)

    Minetti R.

    2006-11-01

    Full Text Available On décrit un nouveau brûleur compact à gaz, de haut rendement et d'une puissance variable de 1 à 5 kW. La source de chaleur est une flamme plate d'un prémélange stoechiométrique de gaz naturel et d'air stabilisé sur une grille d'une surface de 100 cm2. Plusieurs grilles en acier inoxydable sont comparées. Elles diffèrent par leur épaisseur, le nombre et la dimension des trous. Un échangeur de chaleur en laiton à circulation d'eau peut être approché jusqu'à 7 mm de la surface du brûleur. La température des gaz frais, le débit et la position de l'échangeur ont été modifiés et les conditions optimales de fonctionnement sont décrites. Les températures à travers les gaz frais, la flamme, les gaz brûlés et les fumées, ont été mesurées. Un modèle simple des échanges de chaleurs est présenté. Il permet une meilleure compréhension des processus de transfert et facilite le choix des conditions opératoires. Dans les meilleures conditions, 93 % du contenu thermique du mélange gazeux est transféré à l'échangeur. Some general characteristics of a compact and efficient gas burner are described (1-5 kW. The heat source is a premixed flat flame stabilized on a 100 cm2 grid fed by a stoechiometric mixture of air and natural gas. Various types of stainless steel grids have been investigated. They differ according to their thickness and to the number and size of the holes. A circulating water heat exchanger made of brass can be approached to the flame as close as 7 mm above the burner surface. The temperature of the inlet gas mixture, the flow rate, and the position of the heat exchanger have been varied. The best working conditions are given as well as the temperature through the fresh gaseous mixture, the temperature profiles of the flame and the temperature of the fumes. From heat transfer calculations a simple model is presented. It gives better insight into the heat transfer processes and facilitates a judicious

  17. Des journalistes enfin libérés de leurs sources ? Promesse et réalité du "journalisme de données "

    Directory of Open Access Journals (Sweden)

    Sylvain Parasie

    2013-04-01

    Full Text Available Depuis plusieurs années, le traitement de données apparaît à certains journalistes comme une façon de réduire leur dépendance aux sources. En élaborant des bases de données et des algorithmes au sein des rédactions, ils seraient moins tributaires des tuyaux et des interprétations que leur fournissent régulièrement leurs sources, notamment institutionnelles. S’inspirant de la sociologie pragmatique et de la théorie de l’acteur-réseau, cet article montre que les technologies de traitement de données sont actuellement mobilisées afin de permettre aux journalistes de reprendre l’initiative face aux sources. À partir d’une enquête de terrain menée à Chicago en 2010, nous examinons d’abord le contenu de cette promesse apparue au croisement des mondes journalistiques et informatiques. Puis, en étudiant le cas de l’information criminelle à Chicago, nous montrons que cette promesse n’est qu’en partie satisfaite dans les réalisations actuelles. Over the past few years, some journalists have expressed that data processing is a way of reducing their dependence to sources. Elaborating databases and algorithms in the newsrooms is considered to reduce journalists’ need for tips and interpretations from sources, including those institutional. By drawing from pragmatic sociology and the network-actor theory, this article shows that data-processing technologies are currently mobilized to encourage journalists to reinitiate their relation to sources. Based on a study that took place in Chicago in 2010, first we examine the content of the promise that appeared at the intersection of the journalistic and computer science worlds. Then, by analysing criminal news in Chicago, we show that currently, the promise is only partly fulfilled. Há vários anos que alguns jornalistas acreditam que o processamento de dados pode ser uma forma de reduzir sua dependência em relação às fontes de informação. Ao desenvolverem bases de

  18. Multispectral UV imaging for determination of the tablet coating thickness

    DEFF Research Database (Denmark)

    Novikova, Anna; Carstensen, Jens Michael; Zeitler, J. Axel

    2017-01-01

    The applicability of off-line multispectral ultraviolet (UV) imaging in combination with multivariate data analysis was investigated to determine the coating thickness and its distribution on the tablet surface during lab scale coating. The UV imaging results were compared with the weight gain...... measured for each individual tablet and the corresponding coating thickness and its distribution measured by terahertz pulsed imaging (TPI). Three different tablet formulations were investigated, two of which contained UV active tablet cores. Three coating formulations were applied: Aquacoat® ECD (a mainly...... translucent coating) and Eudragit® NE (a turbid coating containing solid particles). It was shown that UV imaging is a fast and non-destructive method to predict individual tablet weight gain as well as coating thickness. The coating thickness distribution profiles determined by UV imaging correlated...

  19. Study of UV-mutagenesis in Bacillus subtilis

    International Nuclear Information System (INIS)

    Lotareva, O.V.; Filippov, V.D.

    1974-01-01

    The sensitivity of Bac. subtilis to the inactivating and mutagenic effects of UV-mutants has been determined: uvr, which does not extract pyrimidine dimers from damaged DNA; recsub(x), which exhibits a reduced activity of ATP-dependent DNAase; poll, which is devoid of DNA polymerase, and wild strains (DT). The sensitivity of these strains to the inactivating effects of UV rays increases in the order: DT<= recsub(x) << uvr < poll, and UV mutability in the order: DT = rec(sub(x) < poll<< uvr. A comparison of UV mutagenesis in Bac. subtilis and E. coli suggests the hypothesis that the mechanisms of UV mutation formation are similar in these two organisms. (author)

  20. Study of UV-induced mutagenesis in Bacillus subtilis

    International Nuclear Information System (INIS)

    Filippov, V.D.; Lotareva, O.V.

    1978-01-01

    The mechanism of UV-induced mutagenesis was studied in Bacillus subtilis departing from the assumption that a lower yield of UV-induced mutations should be found in mutants deficient in the recombination if production of mutations is coupled with the recombination process. Three recombination-deficient strains were used: two (recA and recF) with defects in different recombination pathways and the third (recB) has a block at a stage common for both of them. UV light induced reversions to prototrophy in recB cells and did not in recA and recF strains. Direct mutations, which confer to the cell additional growth requirements, were induced by UV light in recA and recF mutants. It is concluded that UV-induced mutagenesis in B subtilis is independent of the two known recombination mechanisms

  1. The precipitation synthesis of broad-spectrum UV absorber nanoceria

    International Nuclear Information System (INIS)

    Nurhasanah, Iis; Sutanto, Heri; Puspaningrum, Nurul Wahyu

    2013-01-01

    In this paper the possibility of nanoceria as broad-spectrum UV absorber was evaluated. Nanoceria were synthesized by precipitation process from cerium nitrate solution and ammonium hydroxide as precipitant agent. Isopropanol was mixed with water as solvent to prevent hard agglomeration. The structure of resulting nanoceria was characterized by x-ray diffractometer (XRD). The transparency in the visible light and efficiency of protection in UV A region were studied using ultraviolet-visible (UV - Vis) spectrophotometer. The results show that nanoceria possess good tranparency in visible light and high UV light absorption. The critical absorption wavelenght of 368 nm was obtained which is desirable for excellent broad-spectrum protection absorbers. Moreover, analysis of photodegradation nanoceria to methylene blue solution shows poor photocatalytic activity. It indicates that nanoceria suitable for used as UV absorber in personal care products

  2. UV-inducible DNA repair in the cyanobacteria Anabaena spp

    International Nuclear Information System (INIS)

    Levine, E.; Thiel, T.

    1987-01-01

    Strains of the filamentous cyanobacteria Anabaena spp. were capable of very efficient photoreactivation of UV irradiation-induced damage to DNA. Cells were resistant to several hundred joules of UV irradiation per square meter under conditions that allowed photoreactivation, and they also photoreactivated UV-damaged cyanophage efficiently. Reactivation of UV-irradiated cyanophage (Weigle reactivation) also occurred; UV irradiation of host cells greatly enhanced the plaque-forming ability of irradiated phage under nonphotoreactivating conditions. Postirradiation incubation of the host cells under conditions that allowed photoreactivation abolished the ability of the cells to perform Weigle reactivation of cyanophage N-1. Mitomycin C also induced Weigle reactivation of cyanophage N-1, but nalidixic acid did not. The inducible repair system (defined as the ability to perform Weigle reactivation of cyanophages) was relatively slow and inefficient compared with photoreactivation

  3. Solar UV radiation variations and their stratospheric and climatic effects

    Science.gov (United States)

    Donnelly, R. F.; Heath, D. F.

    1985-01-01

    Nimbus-7 SBUV measurements of the short-term solar UV variations caused by solar rotation and active-region evolution have determined the amplitude and wavelength dependence for the active-region component of solar UV variations. Intermediate-term variations lasting several months are associated with rounds of major new active regions. The UV flux stays near the peak value during the current solar cycle variation for more than two years and peaks about two years later than the sunspot number. Nimbus-7 measurements have observed the concurrent stratospheric ozone variations caused by solar UV variations. There is now no doubt that solar UV variations are an important cause of short- and long-term stratospheric variations, but the strength of the coupling to the troposphere and to climate has not yet been proven.

  4. Model of UV flashes due to gigantic blue jets

    International Nuclear Information System (INIS)

    Milikh, G M; Shneider, M N

    2008-01-01

    Analysis of UV flashes observed by the UV detector on board the 'Tatiana' microsatellite suggests, based on their location, pulse width and energy of the source of the photons, that the flashes were generated by gigantic blue jets (GBJs). Presented in this paper is a numerical model of UV flashes due to a bunch of long streamers which form a leader, a prong such as that observed in a GBJ. Using a previously developed model of upward propagation of a long streamer in the exponential atmosphere the paper describes temporal evolution of the UV flux generated by a bunch of long streamers, in the given spectral range 300-400 nm used by the UV detector on board 'Tatiana'. The model is in agreement with the observations.

  5. UV-induced carbon monoxide emission from living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2013-01-01

    The global burden of carbon monoxide (CO) is rather uncertain. In this paper we address the potential for UV-induced CO emission by living terrestrial vegetation surfaces. Real-time measurements of CO concentrations were made with a cavity enhanced laser spectrometer connected in closed loop...... to either an ecosystem chamber or a plant-leaf scale chamber. Leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation as well as the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature......, indicating an abiotic process. The emission of CO in response to the UV-component of natural solar radiation was also evident at the ecosystem scale....

  6. X-UV lasers and their promising applications

    International Nuclear Information System (INIS)

    Ros, D.

    2004-01-01

    The author reviews 30 years of research and achievements concerning X-UV lasers. Typical features of X-UV lasers are: a large number of photons emitted per impulse (between 10 12 and 10 14 ) and very short impulses (between 1 and 100 ps). When a crystal is irradiated by a X-UV laser, these features favor new physical processes that did not appear when the irradiation was performed with other X-UV sources like synchrotron radiation for instance. Their high brilliance and coherence properties make them efficient means as irradiating sources or imaging tools. X-UV laser interferometry allows the mapping of a surface at the nano-metric scale without any interaction between the laser beam and the surface. (A.C.)

  7. Susceptibility of Campylobacter jejuni and Yersinia enterocolitica to UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Butler, R.C.; Lund, V.; Carlson, D.A.

    1987-02-01

    Two enteric pathogens, Campylobacter jejuni and Yersinia enterocolitica serogroup O:3, together with Escherichia coli, were investigated for susceptibility to UV radiation at 254 nm. The UV dose required for a 3-log reduction (99.9% inactivation) of C. jejuni, Y. enterocolitica, and E. coli was 1.8, 2.7, and 5.0 mWs/cm2, respectively. Using E. coli as the basis for comparison, it appears that C. jejuni and Y. enterocolitica serogroup O:3 are more sensitive to UV than many of the pathogens associated with waterborne disease outbreaks and can be easily inactivated in most commercially available UV reactors. No association was found between the sensitivity of Y. enterocolitica to UV and the presence of a 40- to 50-megadalton virulence plasmid.

  8. Susceptibility of Campylobacter jejuni and Yersinia enterocolitica to UV radiation

    International Nuclear Information System (INIS)

    Butler, R.C.; Lund, V.; Carlson, D.A.

    1987-01-01

    Two enteric pathogens, Campylobacter jejuni and Yersinia enterocolitica serogroup O:3, together with Escherichia coli, were investigated for susceptibility to UV radiation at 254 nm. The UV dose required for a 3-log reduction (99.9% inactivation) of C. jejuni, Y. enterocolitica, and E. coli was 1.8, 2.7, and 5.0 mWs/cm2, respectively. Using E. coli as the basis for comparison, it appears that C. jejuni and Y. enterocolitica serogroup O:3 are more sensitive to UV than many of the pathogens associated with waterborne disease outbreaks and can be easily inactivated in most commercially available UV reactors. No association was found between the sensitivity of Y. enterocolitica to UV and the presence of a 40- to 50-megadalton virulence plasmid

  9. Dose effect of the uvsA+ gene product in duplication strains of Aspergillus nidulans

    International Nuclear Information System (INIS)

    Majerfeld, I.H.; Roper, J.A.

    1978-01-01

    Strains of Aspergillus nidulans which carry a particular segment of chromosome I in duplicate - one segment in normal position, the other translocated to chromosome II - are more resistant to uv light than are strains with a balanced haploid genome. A double dose of the uvsA + allele, carried on the duplicate segment, determines this enhanced resistance; this is shown by the descending order of resistance of duplication haploids uvsA + /uvsA + , uvsA1/uvsA + and uvsA1/uvsA1. An unbalanced diploid with three doses of the uvsA + allele also shows greater resistance than a balanced uvsA + //uvsA + diploid. However, in balanced diploids the uvsA1 allele appears to be completely recessive; uvsA + //uvsA + and uvsA + //uvsA1 diploids produce indistinguishable survival curves after uv irradiation. Thus, the uvsA + gene product is not rate-limiting in repair processes in strains with a balanced genome. The rate-limiting effect observed in these unbalanced strains presumably reflects an interaction of the uvsA + product and other functions determined by the rest of the genome. Duplication haploids and normal haploids lose photorepairable lesions at similar rates. This observation may be interpreted to indicate that differences in survival are not due to differences in the efficiency of excision of uv-induced pyrimidime dimers

  10. Study of the effect of the energy spectrum and of the total flux on the damage produced by neutrons in solids; Contribution a l'etude de l'influence du spectre et du flux integre sur les dommages crees par les neutrons dans les solides

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-01-01

    In the first part are studied the general relationships between the physical effects produced by neutrons in solids, and the total flux and neutron energy spectrum; some examples are given. The second part, describes the application to a silicon damage detector whose principle is to use the damage produced in a PIN Junction for measuring the neutron flux (intermediate and fast) received by the detector. Chapter I is devoted to the experimental determination of the energy given to the atoms by a primary in the silicon. The results and conclusions drawn from this determination make it possible to consider, in chapter II, the calculation of the detectors response characteristics.Chapter III deals with the measurement of the detectors response function and it is noted that good agreement is obtained between the calculation and experimental results. The whole of the second part constitutes a test of the methods presented in the first part. (author) [French] Dans la premiere partie, nous etudions les relations generales qui lient les effets physiques engendres par les neutrons dans les solides au flux integre et au spectre des neutrons et nous donnons des exemples d'utilisation. La deuxieme partie est une application au detecteur de dommages en silicium, dont le principe est d'utiliser les dommages crees dans une jonction PIN pour mesurer les flux de neutrons (intermediaires et rapides) recus par le detecteur. Le chapitre I est consacre a la determination experimentale de l'energie cedee aux atomes par un primaire dans le silicium. Les resultats et les conclusions que l'on peut tirer de cette determination permettent d'aborder, au chapitre II, le calcul de la fonction de reponse du detecteur. Le chapitre III porte sur la mesure de la fonction de reponse du detecteur et on constate qu'il y a un bon accord entre le calcul et l'experience. L'ensemble de la deuxieme partie constitue un test des methodes exposees dans la premiere partie. (auteur)

  11. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    KAUST Repository

    Caputo, Fanny; De Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

    2015-01-01

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which

  12. Environmental occurrence and distribution of organic UV stabilizers and UV filters in the sediment of Chinese Bohai and Yellow Seas.

    Science.gov (United States)

    Apel, Christina; Tang, Jianhui; Ebinghaus, Ralf

    2018-04-01

    Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Invloed van UV straling in de kas. Fors minder plaaginsecten bij kasdek dat geen UV-licht doorlaat

    NARCIS (Netherlands)

    Hemming, S.; Os, van E.

    2007-01-01

    Nieuwe energiebesparende kasdekmaterialen hebben een andere doorlatendheid voor UV-straling dan glas. Dat heeft niet alleen invloed op de groei van planten, maar ook op die van plaaginsecten, schimmels, predatoren en bestuivende insecten. In dit artikel komt het effect van UV op plaaginsecten,

  14. Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

    Science.gov (United States)

    Said, T; Dutot, M; Martin, C; Beaudeux, J-L; Boucher, C; Enee, E; Baudouin, C; Warnet, J-M; Rat, P

    2007-03-01

    The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.

  15. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

    International Nuclear Information System (INIS)

    Krizek, D.T.; Britz, S.J.; Mirecki, R.M.

    1998-01-01

    The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au)

  16. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Krizek, D.T.; Britz, S.J.; Mirecki, R.M. [Climate Stress Laboratory, Beltsville, MD (United States)

    1998-05-01

    The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au) 34 refs.

  17. Loss of photoreversibility for UV mutation in E. coli using 405 nm or near-UV challenge

    International Nuclear Information System (INIS)

    Kristoff, S.; Bockrath, R.

    1983-01-01

    E. coli mutagenized with germicidal ultraviolet light (UV) were incubated to allow for development of mutation-fixation processes. Fixation was estimated from the effects on mutation frequency of photoreactivation challenge during the first 60 min post-UV. Two different light sources were used for photoreactivation, one providing effective light primarily at 405 nm and another providing a broad range of near-UV around 365 nm. Kinetics for the loss of photoreversibility (LOP) were determined. The times for completion of LOP in wild-type cells indicated one fixation process for back mutation and another for de novo or converted suppressor mutation regardless of the light source. Using 405-nm light for photoreactivation, the LOP kinetics for back mutation and de novo suppressor mutation in uvrA cells were similar. Hence, classical observations were confirmed here. Immediately post-UV all mutation frequencies were more sensitive to near-UV than 405-nm light. (orig./AJ)

  18. Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

    Science.gov (United States)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

    Key Words: Ultraviolet radiation,Standard Erythema Dose(SED), Minimal Erythema Dose(MED), Sun Burns, Solar Dermatitis, Sun Burned Disease, DNA Damage,Cell Damage, Antiradiation UV Vaccine, Immune-Prophylaxis of Sun Burned Diseases, Immune-Prophylaxis of Sun Burns, Immune-Therapy of Sun-Burned Disease and Sun Burns,Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), Toxic Epidermal Necrolysis(TEN). Introduction: High doses of UV generated by solar source and artificial sources create an exposure of mammals and other species which can lead to ultraviolet(UV)radiation- associated disease (including erythema, epilation, keratitis, etc.). UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm with 100 nm having been chosen arbitrarily as the boundary between non-ionizing and ionizing radiation, however EMR is a spectrum and UV can produce molecular ionization. UV radiation is conventionally categorized into 3 areas: UV-A (>315-400 nm),UV-B (>280-315 nm)and UV-C (>100-280 nm) [IARC,Working Group Reports,2005] An important consequence of stratospheric ozone depletion is the increased transmission of solar ultraviolet (UV)radiation to the Earth's lower atmosphere and surface. Stratospheric ozone levels have been falling, in certain areas, for the past several decades, so current surface ultraviolet-B (UV-B) radiation levels are thought to be close to their modern day maximum. [S.Madronich et al.1998] Overexposure of ultraviolet radiation a major cause of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) { collectively referred to as “non-melanoma" skin cancer (NMSC) and melanoma as well, with skin cancers being the most common cancer in North America. [Armstrong et al. 1993, Gallagher et al. 2005] Methods and Experimental Design: Our experiments and testing of a novel UV “Antiradiation Vaccine” have employed a wide variety of laboratory animals which include : Chinchilla

  19. The Aspergillus uvsH gene encodes a product homologous to yeast RAD18 and Neurospora UVS-2.

    Science.gov (United States)

    Yoon, J H; Lee, B J; Kang, H S

    1995-07-28

    The uvsH DNA repair gene of Aspergillus nidulans has been cloned by complementation of the uvsH77 mutation with a cosmid library containing genomic DNA inserts from a wild-type strain. Methylmethane sulfonate (MMS)-resistant transformants were obtained on medium containing 0.01% MMS, to which uvsH mutants exhibit high sensitivity. Retransformation of uvsH77 mutants with the rescued cosmids from the MMS-resistant transformants resulted in restoration of both UV and MMS resistance to wild-type levels. Nucleotide sequence analysis of the genomic DNA and cDNA of the uvsH gene shows that it has an open reading frame (ORF) of 1329 bp, interrupted by two introns of 51 and 61 bp. A 2.4 kb transcript of the uvsH gene was detected by Northern blot analysis. Primer extension analysis revealed that transcription starts at 31 bp upstream from the translation initiation codon. This gene encodes a predicted polypeptide of 443 amino acids, which has two unique zinc finger motifs. The proposed polypeptide displays 39% identity to the Neurospora crassa UVS-2 protein and 24% identity to the Saccharomyces cerevisiae RAD18 protein. The sequence similarity is particularly high in three domains. One zinc finger (RING finger) motif is located in the first domain close to the N-terminus. The other zinc finger motif is in the second domain. In the third domain, the mutation sites in both the uvsH77 and uvsH304 alleles were identified.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. UV observations of local interstellar medium.

    Science.gov (United States)

    Kurt, V.; Mironova, E.; Fadeev, E.

    2008-12-01

    The methods of the interstellar matter study are described. The brief information of space missions aimed at observations in the unreachable for ground based telescopes UV spectral range (IUE, As- tron, HST and GALEX.) is presented. The history of discovery of H and He atoms entering the Solar System from the local interstellar medium (LISM) is given in brief. The results of observations performed by the group from Stern- berg Astronomical Institute (SAI MSU) and Space Research Institute (IKI RAS) performed with the help of the missions Prognoz-5, Prognoz-6 and the stations Zond-1, Venera and Mars and aimed at estimation of all basic LISM parameters (the velocity of the Sun in relation to LISM, directions of movement, densities of H and He atoms, LISM temperature) are presented. We also describe the present-day investigations of LISM performed with SOHO and ULYSSES mis- sions including the direct registration of He atoms entering the Solar System. The problem of interaction between the incoming flow of the ISM atoms ("in- terstellar wind") and the area of two shocks at the heliopause border (100-200 AU) is discussed. The LISM parameters obtained using the available data are presented in two tables.

  1. Pulsed UV laser technologies for ophthalmic surgery

    International Nuclear Information System (INIS)

    Razhev, A M; Bagayev, S N; Churkin, D S; Kargapol’tsev, E S; Chernykh, V V; Iskakov, I A; Ermakova, O V

    2017-01-01

    The paper provides an overview of the results of multiyear joint researches of team of collaborators of Institute of Laser Physics SB RAS together with NF IRTC “Eye Microsurgery” for the period from 1988 to the present, in which were first proposed and experimentally realized laser medical technologies for correction of refractive errors of known today as LASIK, the treatment of ophthalmic herpes and open-angle glaucoma. It is proposed to carry out operations for the correction of refractive errors the use of UV excimer KrCl laser with a wavelength of 222 nm. The same laser emission is the most suitable for the treatment of ophthalmic herpes, because it has a high clinical effect, combined with many years of absence of recrudescence. A minimally invasive technique of glaucoma operations using excimer XeCl laser (λ=308 nm) is developed. Its wavelength allows perform all stages of glaucoma operations, while the laser head itself has high stability and lifetime, will significantly reduce operating costs, compared with other types of lasers. (paper)

  2. Symbiotic star UV emission and theoretical models

    International Nuclear Information System (INIS)

    Kafatos, M.

    1982-01-01

    Observations of symbiotic stars in the far UV have provided important information on the nature of these objects. The canonical spectrum of a symbiotic star, e.g. RW Hya, Z And, AG Peg, is dominated by strong allowed and semiforbidden lines of a variety of at least twice ionized elements. Weaker emission from neutral and singly ionized species is also present. A continuum may or may not be present in the 1200 - 2000 A range but is generally present in the range 2000 - 3200 A range. The suspected hot subdwarf continuum is seen in some cases in the range 1200 - 2000 A (RW Hya, AG Peg, SY Mus). The presence of an accretion disk is difficult to demonstrate and to this date the best candidate for accretion to a main sequence star remains CI Cyg. A number of equations have been derived by the author that can yield the accretion parameters from the observable quantities. Boundary layer temperatures approximately 10 5 K and accretion rates approximately > 10 -5 solar masses/yr are required for accreting main sequence companions. To this date, though, most of the symbiotics may only require the presence of a approximately 10 5 K hot subdwarf. (Auth.)

  3. Causality violation, gravitational shockwaves and UV completion

    Energy Technology Data Exchange (ETDEWEB)

    Hollowood, Timothy J.; Shore, Graham M. [Department of Physics, Swansea University,Swansea, SA2 8PP (United Kingdom)

    2016-03-18

    The effective actions describing the low-energy dynamics of QFTs involving gravity generically exhibit causality violations. These may take the form of superluminal propagation or Shapiro time advances and allow the construction of “time machines”, i.e. spacetimes admitting closed non-spacelike curves. Here, we discuss critically whether such causality violations may be used as a criterion to identify unphysical effective actions or whether, and how, causality problems may be resolved by embedding the action in a fundamental, UV complete QFT. We study in detail the case of photon scattering in an Aichelburg-Sexl gravitational shockwave background and calculate the phase shifts in QED for all energies, demonstrating their smooth interpolation from the causality-violating effective action values at low-energy to their manifestly causal high-energy limits. At low energies, these phase shifts may be interpreted as backwards-in-time coordinate jumps as the photon encounters the shock wavefront, and we illustrate how the resulting causality problems emerge and are resolved in a two-shockwave time machine scenario. The implications of our results for ultra-high (Planck) energy scattering, in which graviton exchange is modelled by the shockwave background, are highlighted.

  4. UV-Curing of Nanoparticle Reinforced Acrylates

    International Nuclear Information System (INIS)

    Bauer, F.

    2006-01-01

    Polymer reinforcement by silica and alumina nanoparticles evidently yields improved surface hardness. Single mixing of nanoparticles into an acrylate formulations, however, leads to highly viscous solutions inappropriate for coating procedures. The incompatibility of inorganic fillers and organic polymers can be avoided by surface modification providing an interface between the two dissimilar materials. For example, vinyltrimethoxysilane (VTMO) can react via hydrolysis/condensation reactions with hydroxyl groups present on the inorganic surface and should bond via the polymerisation-active vinyl group to an acrylate resin through crosslinking reactions. Grafting reactions of surface OH groups and different trialkoxysilanes were studied by thermogravimetry, infrared, and multinuclear NMR spectroscopy. The copolymeri-zation of modified nanoparticles with the acrylate matrix has been investigated by 13 C NMR spectroscopy. UV curing under nitrogen inertization revealed a lower reactivity of vinyl groups of VTMO-modified silica compared to grafted methacryloxypropyl-trimethoxysilane (MEMO) which showed complete conversion of olefinic carbons (signals at 120 - 140 ppm). Under conditions of oxygen inhibition, the effect of the kind and the concentration of photoinitiator on the photopoly-merization reaction was studied. Compared to neat polyacrylate coatings the nanocomposite materials exhibit markedly improved properties, e.g., heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nano-particles and corundum microparticles. In particular cases, radiation curing with 172 nm photons generated by Xe excimer was performed to obtain structured polymer surfaces, i.e., matting of the reinforced acrylate coatings

  5. In Vitro Repair of UV-Irradiated Micrococcus luteus Bacteriophage N1 Transfecting DNA 1

    Science.gov (United States)

    Mahler, Inga; George, Jeanne; Grossman, Lawrence

    1974-01-01

    Calcium-treated UV-sensitive, host cell reactivation− strains of Micrococcus luteus are infected with UV-irradiated N1 DNA. In strains lacking UV endonuclease, in vitro treatment of the irradiated DNA results in transfection enhancement. PMID:4823319

  6. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    KAUST Repository

    Garcia-Corral, Lara S.; Martinez Ayala, Juan; Duarte, Carlos M.; Agusti, Susana

    2015-01-01

    . The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely

  7. Study on DNA damages induced by UV radiation

    International Nuclear Information System (INIS)

    Doan Hong Van; Dinh Ba Tuan; Tran Tuan Anh; Nguyen Thuy Ngan; Ta Bich Thuan; Vo Thi Thuong Lan; Tran Minh Quynh; Nguyen Thi Thom

    2015-01-01

    DNA damages in Escherichia coli (E. coli) exposed to UV radiation have been investigated. After 30 min of exposure to UV radiation of 5 mJ/cm"2, the growth of E. coli in LB broth medium was about only 10% in compared with non-irradiated one. This results suggested that the UV radiation caused the damages for E. coli genome resulted in reduction in its growth and survival, and those lesions can be somewhat recovered. For both solutions of plasmid DNAs and E. coli cells containing plasmid DNA, this dose also caused the breakage on single and double strands of DNA, shifted the morphology of DNA plasmid from supercoiled to circular and linear forms. The formation of pyrimidine dimers upon UV radiation significantly reduced when the DNA was irradiated in the presence of Ganoderma lucidum extract. Thus, studies on UV-induced DNA damage at molecular level are very essential to determine the UV radiation doses corresponding to the DNA damages, especially for creation and selection of useful radiation-induced mutants, as well as elucidation the protective effects of the specific compounds against UV light. (author)

  8. Skin β-endorphin mediates addiction to UV light.

    Science.gov (United States)

    Fell, Gillian L; Robinson, Kathleen C; Mao, Jianren; Woolf, Clifford J; Fisher, David E

    2014-06-19

    UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed and reversed by pharmacologic opioid antagonism. Opioid blockade also elicits withdrawal signs after chronic UV exposure. This effect was sufficient to guide operant behavioral choices to avoidance of opioid withdrawal (conditioned place aversion). These UV-induced nociceptive and behavioral effects were absent in β-endorphin knockout mice and in mice lacking p53-mediated POMC induction in epidermal keratinocytes. Although primordial UV addiction, mediated by the hedonic action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in humans. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Contribution to the micro-calorimetric study of the characteristics of radio-elements and to their qualitative and quantitative analysis; Contribution a l'etude microcalorimetrique des caracteristiques des radio-elements et a leurs analyses qualitative et quantitative

    Energy Technology Data Exchange (ETDEWEB)

    Ozias, Y [Centre de Production de Plutonium de Marcoule, 30 (France)

    1964-10-01

    equal to that obtained by mass spectrography (destruction of the sample) 1 to 3 per cent, and higher than that obtained by counting techniques (greater than 5 per cent). (author) [French] Le principe de cette etude consiste a enregistrer avec le microcalorimetre E. CALVET le flux d'energie emis par les radioelements en fonction du temps at a partir de cette courbe de determiner soit leurs caracteristiques (periode et energie du rayonnement), soit la composition d'un melange de radioelements. Dans une premiere partie on a adapte les relations theoriques de la radioactivite a l'etude microcalorimetrique. Dans une deuxieme partie on determine experimentalement au microcalorimetre E. CALVET les caracteristiques de divers radioelements, yttrium 90, phosphore 32, soufre 35, iode 131, etc. et leurs melanges. On a etudie plus particulierement l'analyse isotopique du melange de {sup 239}Pu, de {sup 240}Pu et eventuellement de {sup 241}Pu. La methode microcalorimetrique n'a pas la sensibilite des methodes classiques de comptage, sa limite actuelle para etre de l'ordre du micro-watt pour les appareils utilises, mais elle est la plus directe pour les emetteurs de rayonnements facilement absorbables({alpha} et {beta}). Pour les emetteurs {gamma} une partie seulement de l'energie est absorbee par les parois du recipient. La determination de leurs caracteristiques et de leurs masses dans les melanges ne depend ni de la forme, ni de la dilution, ni surtout de l'auto-absorption de la source. Pour des echantillons de forte activite, cette auto-absorption est pour les methodes classiques la source de grosses difficultes entra ant de multiples manipulations: divisions, mise en solution, dilutions qui introduisent autant de causes d'erreur. La methode calorimetrique permet de travailler sur l'echantillon brut. Toutes les mesures ont ete faites avec le microcalorimetre E. CALVET classique; mais pour effectuer une mesure tres precise de' l'energie due au rayonnement {gamma} il faut faire

  10. Livingston-Courant magnetic lens and their use in focussing a beam supplied by a Van der Graaff; Lentilles magnetiques Courant-Livingston et leur utilisation a la focalisation du faisceau donne par un Van de Graaff

    Energy Technology Data Exchange (ETDEWEB)

    Gendreau, G.

    1953-11-15

    This technical note presents the general calculation of focal distances of a system made of two crossed thick lens. It outlines that these lens can be considered as thin lens in their operation domain (focal distance comprised between an element length and the infinite), and then elaborated formula for all optical elements. These formula are then applied to lens built for the Van der Graaff. The actual length of a lens is then given with respect to its theoretical length. Obtained numerical values lead to the determination of magnetic and mechanical characteristics of a lens [French] Le calcul general des distances focales d'un systeme de deux lentilles epaisses croisees est explicite. Dans leur domaine d'utilisation (distances focales comprises entre l'infini et la longueur d'un element) on peut les considerer comme minces, tous les elements optiques sont alors formules. L'application de ces formules aux lentilles construites pour le Van de Graaff se traduit par les tableaux I et II. On donne la longueur reelle d'une lentille en fonction de sa longueur theorique. Les valeurs numeriques trouvees conduisent a la determination des caracteristiques magnetiques et mecaniques d'une lentille. (auteur)

  11. Niger Republic mineral planning : Part four Second volume : Main mineral substances specific study and their geological context; Plan mineral de la Republique du Niger : Tome IV : 2e Volume : Etude specifique des principales substances minerales et leur contexte geologique

    Energy Technology Data Exchange (ETDEWEB)

    Franconi, Antoine; Joo' , Julien; Zibo, Idde

    1981-07-01

    This volume describes Niger Republic mineral substances capable of rising economic interest. After relating minerals occurrence , indices and deposits types, conclusions and recommendations have been made for mineral prospecting. Mineral substances described are : Copper, lead and zinc, molybdena, iron, manganese, titanium, vanadium, nickel and chrome ( cobalt and platinoid ), lithium, lignite, diamond and diverse substances rare earth, beryllium, silver, bismuth arsenic and antimony, barytine, alunite, talc and asbestos ( graphite and diatomite) [French] Ce volume decrit les substances susceptibles de presenter un interet economique au Niger. Apres avoir relate leurs occurrences , indices et types de gisement auxquels elles appartiennent des conclusions et recommendations ont ete faites pour la prospection. Les substances ainsi decrites sont : le cuivre, le plomb et le zinc, le molybdene, le fer, le manganese, le titane et le vanadium, le nickel et le chrome (Cobalt et platinoides), le lithium, le lignite, le diamant et les substances diverses ( terres rares, beryllium), argent, bismuth, arsenic et antimoine, barytine, alunite, talc et amiante (graphite et diatomite)

  12. Contribution des causes de décès aux gains en espérance de vie à 65 ans au Canada et l’influence de leur profil par âge, 1979-2007

    DEFF Research Database (Denmark)

    Bergeron Boucher, Marie-Pier

    variation par âge des causes de décès influencent les tendances des taux de mortalité par cause. Les résultats montrent que les progrès de l’espérance de vie à 65 ans sont encore majoritairement dus à la diminution de la mortalité liée aux maladies cardiovasculaires. Toutefois, ces dernières causes de décès...... dans l’évolution de l’espérance de vie proviennent de modifications dans les tendances de certaines causes de décès et de leurs interactions. Cette étude analyse la contribution respective de certaines causes de décès aux changements observés de l’espérance de vie, mais aussi comment les profils de...... ne sont pas les seules à contribuer aux progrès en espérance de vie, puisque les taux de mortalité des dix principales causes de décès au Canada ont connu une diminution depuis 1979, malgré des profils de variation par âge différents....

  13. Utilisation des huiles végétales et de leurs produits de transestérification comme carburants Diesel Use of Vegetable Oils and Their Transesterification Products As Diesel Fuels

    Directory of Open Access Journals (Sweden)

    Gateau P.

    2006-11-01

    Full Text Available L'utilisation d'huiles végétales et de leurs dérivés comme carburants Diesel a fait l'objet, depuis 1981, de plusieurs études financées par l'Agence Française pour la Maîtrise de l'Energie (AFME et réalisées par l'institut Français du Pétrole (lFP en collaboration avec Elf Renault, le Centre d'Etudes et d'Expérimentation du Machinisme Agricole Tropical (CEEMAT et l'institut de Recherches pour les Huiles et Oléagineux (IRHO. Ce document rassemble les résultats obtenus au banc d'essai sur plusieurs types de moteurs représentant un assez large éventail d'applications, depuis le motoculteur utilisé en agriculture africaine jusqu'au moteur classique de tracteur ou de camion. Deux types de produits ont été examinés : les huiles végétales elles-mêmes employées pures ou en mélange au gazole, et les esters méthyliques de ces huiles utilisés tels quels. Lors d'un fonctionnement de courte durée les huiles aussi bien que les esters conduisent globalement à un fonctionnement satisfaisant du moteur; les pertes de performances par rapport au gazole restent modérées voire imperceptibles. Les seuls problèmes dans ce cas concernent la mise en oeuvre, difficile avec les huiles en raison de leur très forte viscosité, beaucoup plus aisée avec les esters. En endurance, l'inconvénient majeur des huiles végétales et de leurs dérivés concerne la formation de dépôts au nez des injecteurs. Sur les moteurs rustiques à préchambre (type Hatz ce phénomène reste limité puisqu'il a été possible de conduire, sans incident, un ensemble d'essais d'endurance de 1100 h avec différents types d'huiles pures (arachide, coton, palme. Sur les moteurs à Injection directe la formation de dépôts constitue une très sérieuse contrainte puisqu'elle conduit pratiquement à proscrire l'utilisation d'huiles même en mélange (25 ou 50 % dans le gazole. Les esters peuvent alors être proposés à condition qu'un certain nombre de pr

  14. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Blasberger, Avi; Behar, Ehud; Perets, Hagai B. [Department of Physics, Technion (Israel); Brosch, Noah [The Wise Observatory and School of Physics and Astronomy, Tel Aviv University (Israel); Tielens, Alexander G. G. M. [Leiden Observatory, Leiden University (Netherlands)

    2017-02-20

    The 2175 Å UV extinction feature was discovered in the mid-1960s, yet its physical origin remains poorly understood. One suggestion is absorption by polycyclic aromatic hydrocarbon (PAH) molecules, which is supported by theoretical molecular structure computations and by laboratory experiments. PAHs are positively detected by their 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m IR emission bands, which are specified by their modes of vibration. A definitive empirical link between the 2175 Å UV extinction and the IR PAH emission bands, however, is still missing. We present a new sample of hot stars that have both 2175 Å absorption and IR PAH emission. We find significant shifts of the central wavelength of the UV absorption feature, up to 2350 Å, but predominantly in stars that also have IR PAH emission. These UV shifts depend on stellar temperature in a fashion that is similar to the shifts of the 6.2 and 7.7 μ m IR PAH bands, that is, the features are increasingly more redshifted as the stellar temperature decreases, but only below ∼15 kK. Above 15 kK both UV and IR features retain their nominal values. Moreover, we find a suggestive correlation between the UV and IR shifts. We hypothesize that these similar dependences of both the UV and IR features on stellar temperature hint at a common origin of the two in PAH molecules and may establish the missing link between the UV and IR observations. We further suggest that the shifts depend on molecular size, and that the critical temperature of ∼15 kK above which no shifts are observed is related to the onset of UV-driven hot-star winds and their associated shocks.

  15. UV filters bioaccumulation in fish from Iberian river basins

    Energy Technology Data Exchange (ETDEWEB)

    Gago-Ferrero, Pablo [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens (Greece); Díaz-Cruz, M. Silvia, E-mail: sdcqam@cid.csic.es [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Barceló, Damià [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, C/ Emili Grahit, 101 Edifici H2O, E-17003 Girona (Spain)

    2015-06-15

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification.

  16. UV filters bioaccumulation in fish from Iberian river basins

    International Nuclear Information System (INIS)

    Gago-Ferrero, Pablo; Díaz-Cruz, M. Silvia; Barceló, Damià

    2015-01-01

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification

  17. Risks of increased UV-B radiation: higher plants

    International Nuclear Information System (INIS)

    Rau, W.; Hofmann, H.

    1994-01-01

    The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

  18. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  19. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    International Nuclear Information System (INIS)

    Blasberger, Avi; Behar, Ehud; Perets, Hagai B.; Brosch, Noah; Tielens, Alexander G. G. M.

    2017-01-01

    The 2175 Å UV extinction feature was discovered in the mid-1960s, yet its physical origin remains poorly understood. One suggestion is absorption by polycyclic aromatic hydrocarbon (PAH) molecules, which is supported by theoretical molecular structure computations and by laboratory experiments. PAHs are positively detected by their 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m IR emission bands, which are specified by their modes of vibration. A definitive empirical link between the 2175 Å UV extinction and the IR PAH emission bands, however, is still missing. We present a new sample of hot stars that have both 2175 Å absorption and IR PAH emission. We find significant shifts of the central wavelength of the UV absorption feature, up to 2350 Å, but predominantly in stars that also have IR PAH emission. These UV shifts depend on stellar temperature in a fashion that is similar to the shifts of the 6.2 and 7.7 μ m IR PAH bands, that is, the features are increasingly more redshifted as the stellar temperature decreases, but only below ∼15 kK. Above 15 kK both UV and IR features retain their nominal values. Moreover, we find a suggestive correlation between the UV and IR shifts. We hypothesize that these similar dependences of both the UV and IR features on stellar temperature hint at a common origin of the two in PAH molecules and may establish the missing link between the UV and IR observations. We further suggest that the shifts depend on molecular size, and that the critical temperature of ∼15 kK above which no shifts are observed is related to the onset of UV-driven hot-star winds and their associated shocks.

  20. Impact of UV Radiation on Genome Stability and Human Health.

    Science.gov (United States)

    Roy, Sujit

    2017-01-01

    Gradual depletion of the atmospheric ozone layer during the past few years has increased the incidence of solar UV radiation specifically the UV-C on earth's surface is one of the major environmental concerns because of the harmful effects of this radiation in all forms of life. The solar UV radiation including the harmful wavelength range of UV-B (280-320 nm) represents a significant climatic stress for both animals and plants, causing damage to the fundamental biomolecules such as DNA, proteins and lipids, thus activating genotoxic stress and induces genome instability. When DNA absorbs UV-B light, energy from the photon causes covalent linkages to form between adjacent pyrimidine bases, creating photoproducts, primarily cyclobutane pyrimidine dimers (CPDs) and pyrimidine-6,4-pyrimidinone photoproduct (6,4PPs). Pyrimidine dimers create distortions in the DNA strands and therefore can inhibit DNA replication as well transcription. Lack of efficient repair of UV-induced DNA damage may induce the formation of DNA double stand breaks (DSBs), one of the serious forms of damage in DNA double helix, as well as oxidative damage. Unrepaired DSBs in the actively dividing somatic cells severely affect cell growth and development, finally results in loss of cell viability and development of various diseases, such as cancer in man.This chapter mainly highlights the incidence of solar UV-radiation on earth's surface along with the formation of major types of UV-induced DNA damage and the associated repair mechanisms as well as methods of detecting DNA damage and finally our present understanding on the impact on solar UV radiation on human health.

  1. Liquid egg white pasteurization using a centrifugal UV irradiator.

    Science.gov (United States)

    Geveke, David J; Torres, Daniel

    2013-03-01

    Studies are limited on UV nonthermal pasteurization of liquid egg white (LEW). The objective of this study was to inactivate Escherichia coli using a UV irradiator that centrifugally formed a thin film of LEW on the inside of a rotating cylinder. The LEW was inoculated with E. coli K12 to approximately 8 log cfu/ml and was processed at the following conditions: UV intensity 1.5 to 9.0 mW/cm²; cylinder rotational speed 450 to 750 RPM, cylinder inclination angle 15° to 45°, and flow rate 300 to 900 ml/min, and treatment time 1.1 to 3.2s. Appropriate dilutions of the samples were pourplated with tryptic soy agar (TSA). Sublethal injury was determined using TSA+4% NaCl. The regrowth of surviving E. coli during refrigerated storage for 28 days was investigated. The electrical energy of the UV process was also determined. The results demonstrated that UV processing of LEW at a dose of 29 mJ/cm² at 10°C reduced E. coli by 5 log cfu/ml. Inactivation significantly increased with increasing UV dose and decreasing flow rate. The results at cylinder inclination angles of 30° and 45° were similar and were significantly better than those at 15°. The cylinder rotational speed had no significant effect on inactivation. The occurrence of sublethal injury was detected. Storage of UV processed LEW at 4° and 10°C for 21 days further reduced the population of E. coli to approximately 1 log cfu/ml where it remained for an additional 7 days. The UV energy applied to the LEW to obtain a 5 log reduction of E. coli was 3.9 J/ml. These results suggest that LEW may be efficiently pasteurized, albeit at low flow rates, using a nonthermal UV device that centrifugally forms a thin film. Published by Elsevier B.V.

  2. Significant role of UV and carbonate radical on the degradation of oxytetracycline in UV-AOPs: Kinetics and mechanism.

    Science.gov (United States)

    Liu, Yiqing; He, Xuexiang; Duan, Xiaodi; Fu, Yongsheng; Fatta-Kassinos, Despo; Dionysiou, Dionysios D

    2016-05-15

    Carbonate radical (CO3(•-)), a selective oxidant, reacts readily with electron-rich compounds through electron transfer and/or hydrogen abstraction. In this study, the role of CO3(•-) in degrading oxytetracycline (OTC) by UV only, UV/H2O2 and UV/persulfate (UV/PS) advanced oxidation processes (AOPs) in the presence of HCO3(-) or CO3(2-) was investigated. For UV only process, the presence of photosensitizers, i.e., nitrate (NO3(-)) and natural organic matter (NOM), had different impacts on OTC degradation, i.e., an enhancing effect by NO3(-) due to the generation of HO(•) and a slight inhibiting effect by NOM possibly due to a light scattering effect. Differently for UV/H2O2 and UV/PS processes, the presence of NO3(-) hardly influenced the destruction of OTC. Generation of CO3(•-) presented a positive role on OTC degradation by UV/NO3(-)/HCO3(-). Such influence was also observed in the two studied AOPs in the presence of both bicarbonate and other natural water constituents. When various natural water samples from different sources were used as reaction matrices, UV only and UV/H2O2 showed an inhibiting effect while UV/PS demonstrated a comparable or even promoting effect in OTC decomposition. After elucidating the potential contribution of UV direct photolysis via excited state OTC* at an elevated reaction pH condition, putative OTC transformation byproducts via CO3(•-) reaction were identified by ultra-high definition accurate-mass quadrupole time-of-flight tandem mass spectrometry (QTOF/MS). Five different reaction pathways were subsequently proposed, including hydroxylation (+16 Da), quinonization (+14 Da), demethylation (-14 Da), decarbonylation (-28 Da) and dehydration (-18 Da). The significant role of UV at high pH and CO3(•-) on OTC removal from contaminated water was therefore demonstrated both kinetically and mechanistically. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Cremophor EL stimulates mitotic recombination in uvsH//uvsH diploid strain of Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Cleverson Busso

    2004-03-01

    Full Text Available Cremophor EL is a solubilizer and emulsifier agent used in the pharmaceutical and foodstuff industries. The solvent is the principal constituent of paclitaxel's clinical formulation vehicle. Since mitotic recombination plays a crucial role in multistep carcinogenesis, the study of the recombinagenic potential of chemical compounds is of the utmost importance. In our research genotoxicity of cremophor EL has been studied by using an uvsH//uvsH diploid strain of Aspergillus nidulans. Since it spends a great part of its cell cycle in the G2period, this fungus is a special screening system for the study of mitotic recombination induced by chemical substances. Homozygotization Indexes (HI for paba and bi markers from heterozygous B211//A837 diploid strain were determined for the evaluation of the recombinagenic effect of cremophor EL. It has been shown that cremophor EL induces increase in mitotic crossing-over events at nontoxic concentrations (0.05 and 0.075% v/v.Cremofor EL (CEL é um solubilizante e emulsificante amplamente utilizado nas indústrias farmacêuticas e de gêneros alimentícios. É o principal veículo empregado nas formulações clínicas do antineoplásico paclitaxel. Considerando-se que a recombinação mitótica desempenha importante função no processo de carcinogênese, o estudo de substâncias químicas com potencial recombinagênico assume importância crucial, no sentido de se detectar aquelas que eventualmente possam atuar como promotoras de neoplasias. A genotoxicidade do cremofor EL foi estudada no presente trabalho, utilizando-se uma linhagem diplóide uvsH//uvsH de Aspergillus nidulans. Neste fungo as células vegetativas comumente repousam no período G2 do ciclo celular, facilitando a ocorrência da recombinação mitótica. O efeito recombinagênico do CEL foi avaliado através da determinação dos Índices de Homozigotização para os marcadores nutricionais paba e bi do diplóide heterozigoto B211//A837. Os

  4. Effects of UV radiation on the UV-VIS absorption spectra of the EAGLE's medium components

    International Nuclear Information System (INIS)

    Bollmann, G.; Redmann, K.

    1990-01-01

    The impact of ultraviolet light on uv/vis absorption spectra of selected individual components of the cell breeding medium according to Eagle (MEM) was investigated. The strongest alterations of light absorption were detected in L-phenylalanin, L-tyrosin and L-tryptophane. Thus, the absorption behaviour of the Eagle (MEM) medium changed post radiationem may be attributed to spectrophotometric alterations of absorption in aromatic amino acids. The results are discussed with regard to the effect on the surface charge of erythrocytes. (author)

  5. Effect of UV on building materials in New Zealand

    International Nuclear Information System (INIS)

    Bennett, A.F.

    1993-01-01

    Building materials can be divided into two main classes; organic or polymeric based and inorganic materials. Inorganic materials are in most cases largely unaffected by UV radiation. Many common polymers have bonds sensitive to radiation in the UV region. Absorption of radiation of these wavelengths will lead to excitation of electrons which can lead to isomerisation, chain scissors, cross linking and free radical formation. It is worth noting that the effects of UV radiation are always acting synergistically with other environmental effects. (author). 4 refs., 2 tabs

  6. Inhibition of photosystem II by UV-B-radiation

    International Nuclear Information System (INIS)

    Tevini, M.; Pfister, K.

    1985-01-01

    The effect of UV-B-radiation on PSII activity of spinach chloroplasts was analyzed by measuring the integrity of the herbicide-binding protein (HBP 32), by measurement of fluorescence induction in the presence of Diuron (DCMU), and by mathematical analysis of the fluorescence induction curves. It was shown that UV-B inactivates the PSII α-centers but not PSII β-centers. However, the possibility cannot be excluded that in addition the donor site of PSII near the reaction center is attacked by UV-B-radiation. (orig.)

  7. Effect of enhanced UV-B radiation on motile microorganisms

    International Nuclear Information System (INIS)

    Haeder, D.P.

    1985-02-01

    The effect of slightly increased UV-B radiation was studied in four taxonomically very different microorganisms: the gliding prokaryotic cyanobacterium, Phormidium, the unicellular green alga Cosmarium, the flagellate Euglena and the cellular slime mold Dictyostelium. UV-B doses which can be expected as a result of a slight decrease of the protective ozone layer in the stratosphere, do not kill or damage the microorganisms visibly. However, such UV-B doses impair the development, motility and photoorientation of these organisms. Due to the inhibition of these physiological important parameters the organisms cannot respond adequately to the changing factors in their environment, which prevents the survival of the populations. (orig.) [de

  8. UV irradiation promotes the accumulation of triglyceride in Lipomyces lipofer

    International Nuclear Information System (INIS)

    Konno, A.; Suzuki, Y.; Ogawa, T.; Taniuchi, T.

    2009-01-01

    Yeasts of the genus Lipomyces are known as fat yeasts, and they store large amounts of lipids. Because the major lipid produced by Lipomyces is triglyceride, which can be used as a food and energy resource, the control of lipid production by Lipomyces sp. is an important issue. Here we report the effects of UV irradiation on lipid production in Lipomyces lipofer cells. UV irradiation (315-400 nm) led to a 4-fold increase in the amount of triglyceride per cell. We discovered a novel phenomenon, that UV irradiation promotes triglyceride accumulation in L. lipofer. (author)

  9. UV-enhanced reactivation in mammalian cells: increase by caffeine

    International Nuclear Information System (INIS)

    Lytle, C.D.; Iacangelo, A.L.; Lin, C.H.; Goddard, J.G.

    1981-01-01

    It has been reported that caffeine decreases UV-enhanced reactivation of UV-irradiated Herpes simplex virus in CV-l monkey kidney cells. That occurred when there was no delay between cell irradiation and virus infection. In the present study, virus infection was delayed following cell irradiation to allow an 'induction' period separate from the 'expression' period which occurs during the virus infection. Thus, the effects of caffeine on 'induction' and 'expression' could be determined separately. Caffeine increased the expression of UV-enhanced reactivation, while causing a small decrease in the 'induction' of enhanced reactivation. (author)

  10. UV-B damage amplified by transposons in maize

    International Nuclear Information System (INIS)

    Walbot, V.

    1999-01-01

    While absorbing visible light energy for photosynthesis, plants are unavoidably exposed to ultraviolet radiation, which is particularly harmful at shorter wavelengths (UV-B radiation). Ozone depletion in the atmosphere means that plants receive episodic or steadily increasing doses of UV-B, which damages their photosynthetic reaction centres, crosslinks cellular proteins, and induces mutagenic DNA lesions. Plant adaptive mechanisms of shielding and repair are therefore critical to survival — for example, somatic tissues of maize and Arabidopsis defective in phenolic sunscreen pigments incur increased DNA damage, and mutants defective in DNA repair are killed by UV-B

  11. UV-B effect on constituents of Azolla caroliniana.

    Science.gov (United States)

    Ibrahim, Mohamed M; Mostafa, Eazaz M

    2007-01-01

    Changes in growth and ultrastructure of Azolla caroliniana in response to elevated UV-B radiation were investigated. Exposure of plants to UV-B radiation for 1, 8, 16, 24 and 48 h exhibited a significant decrease in biomass and relative growth rate. This decrease resulted in an increase in doubling time over the control. Also, Chl a and b contents were significantly decreased especially after 16 h. The reduction was accompanied by a decrease in 5-aminolaevulinic acid content (precursor of chlorophyll). On the other hand, contents of carotenoid and UV-absorbing phenolic compounds (flavonoids and anthocyanins) were increased.

  12. Improving radiochromic film's sensitivity by wrapping it with UV phosphor

    International Nuclear Information System (INIS)

    Geso, Moshi; Ackerly, Trevor; Patterson, William

    2004-01-01

    The main advantage of radiochromic-film dosimeters is the coupling of rapid full planar-acquisition, high-spatial resolution and dose linearity. Their main limitation, however, is their low radiation sensitivity. This precludes their application to measuring doses below a few Gy. Radiochromic films are sensitive to ultraviolet radiation. In this note the results of exposing radiochromic films to x rays through an UV imaging cassette, which converts and amplifies x rays to UV radiation, are presented. These results indicate a clear increase (around 50%) in radiochromic film's sensitivity to MV x rays (6, 10, and 18 MV) when exposed through the UV phosphor

  13. UV emissions from low energy artificial light sources.

    Science.gov (United States)

    Fenton, Leona; Moseley, Harry

    2014-01-01

    Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. UV, visible and IR laser interaction with gelatine

    International Nuclear Information System (INIS)

    Oujja, M; Rebollar, E; Abrusci, C; Amo, A Del; Catalina, F; Castillejo, M

    2007-01-01

    In this work we investigate the effects on gelatine films of nanosecond pulsed laser irradiation at different laser wavelengths from the UV to the IR at 248, 266, 355, 532 and 1064 nm. We compared gelatines differing in gel strength values (Bloom 75 and 225) and in crosslinking degree. Formation of bubbles at the wavelengths in the UV (248 and 266 nm), melting and resolidification at 355 nm, and formation of craters by ablation in the VIS and IR (532 and 1064 nm) are the observed morphological changes. On the other hand, changes of the fluorescence behaviour of the films upon UV irradiation reveal chemical modifications of photolabile chromophores

  15. Kinetic removal of haloacetonitrile precursors by photo-based advanced oxidation processes (UV/H2O2, UV/O3, and UV/H2O2/O3).

    Science.gov (United States)

    Srithep, Sirinthip; Phattarapattamawong, Songkeart

    2017-06-01

    The objective of the study is to evaluate the performance of conventional treatment process (i.e., coagulation, flocculation, sedimentation and sand filtration) on the removals of haloacetonitrile (HAN) precursors. In addition, the removals of HAN precursors by photo-based advanced oxidation processes (Photo-AOPs) (i.e., UV/H 2 O 2 , UV/O 3 , and UV/H 2 O 2 /O 3 ) are investigated. The conventional treatment process was ineffective to remove HAN precursors. Among Photo-AOPs, the UV/H 2 O 2 /O 3 was the most effective process for removing HAN precursors, followed by UV/H 2 O 2 , and UV/O 3 , respectively. For 20min contact time, the UV/H 2 O 2 /O 3 , UV/H 2 O 2 , and UV/O 3 suppressed the HAN formations by 54, 42, and 27% reduction. Increasing ozone doses from 1 to 5 mgL -1 in UV/O 3 systems slightly improved the removals of HAN precursors. Changes in pH (6-8) were unaffected most of processes (i.e., UV, UV/H 2 O 2 , and UV/H 2 O 2 /O 3 ), except for the UV/O 3 system that its efficiency was low in the weak acid condition. The pseudo first-order kinetic constant for removals of dichloroacetonitrile precursors (k' DCANFP ) by the UV/H 2 O 2 /O 3 , UV/H 2 O 2 and standalone UV systems were 1.4-2.8 orders magnitude higher than the UV/O 3 process. The kinetic degradation of dissolved organic nitrogen (DON) tended to be higher than the k' DCANFP value. This study firstly differentiates the kinetic degradation between DON and HAN precursors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Semi-conservative synthesis of DNA in UV-sensitive mutant cells of Chinese hamster after UV-irradiation

    International Nuclear Information System (INIS)

    Vikhanskaya, F.L.; Khrebtukova, I.A.; Manuilova, E.S.

    1985-01-01

    A study was made of the rate of semi-conservative DNA synthesis in asynchronous UV-resistant (clone V79) and UV-sensitive clones (VII and XII) of Chinese hamster cells after UV-irradiation. In all 3 clones studied, UV-irradiation (5-30 J/m 2 ) induced a decrease in the rate of DNA synthesis during the subsequent 1-2 h. In the resistant clone (V79) recovery of DNA synthesis rate started after the first 2 h post-irradiation (5 J/m 2 ) and by the 3rd hour reached its maximum value, which constituted 70% of that observed in control, non-irradiated cells. The UV-sensitive mutant clones VII and XII showed no recovery in the rate of DNA synthesis during 6-7 h post-irradiation. The results obtained show that the survival of cells is correlated with the ability of DNA synthesis to recover after UV-irradiation in 3 clones studied. The observed recovery of UV-inhibited DNA synthesis in mutant clones may be due to certain defects in DNA repair. (orig.)

  17. Specific inhibition of cytotoxic memory cells produced against uv-induced tumors in uv-irradiation mice

    International Nuclear Information System (INIS)

    Thorn, R.M.

    1978-01-01

    Cytotoxic responses of uv-irradiated mice against syngeneic uv-induced tumors were measured by using a 51 Cr-release assay to determine if uv treatment induced a specific reduction of cytotoxic activity. The in vivo and in vitro primary responses against syngeneic tumors and allogeneic cells were unaffected, as was the ''memory'' response (in vivo stimulation, in vitro restimulation) against alloantigens. In contrast, the memory response of uv-treated mice against syngeneic, uv-induced tumors was consistently and significantly depressed. The cytotoxicity generated by tumor cell stimulation in vivo or in vitro was tumor-specific and T cell-dependent. Since the primary response against syngeneic uv-induced tumors produces apparently normal amounts of tumor-specific cytotoxic activity, uv-treated mice may not reject transplanted syngeneic tumors because of too few T effector memory cells. These results imply that, at least in this system, tumor rejection depends mostly on the secondary responses against tumor antigens and that at least one carcinogen can, indirectly, specifically regulate immune responses

  18. In vivo activation of human immunodeficiency virus type 1 long terminal repeat by UV type A (UV-A) light plus psoralen and UV-B light in the skin of transgenic mice

    OpenAIRE

    Morrey, John D; Bourn, S M; Bunch, T D; Jackson, M K; Sidwell, R W; Barrows, L R; Daynes, R A; Rosen, C A

    1991-01-01

    UV irradiation has been shown to activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in cell culture; however, only limited studies have been described in vivo. UV light has been categorized as UV-A (400 to 315 nm), -B (315 to 280 nm), or -C (less than 280 nm); the longer wavelengths are less harmful but more penetrative. Highly penetrative UV-A radiation constitutes the vast majority of UV sunlight reaching the earth's surface but is normally harmless. UV-B ir...

  19. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    Science.gov (United States)

    Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

    2015-09-01

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

  20. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    KAUST Repository

    Caputo, Fanny

    2015-08-20

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields. © The Royal Society of Chemistry 2015.

  1. Discharge of viscous UV-curable resin droplets by screen printing for UV nanoimprint lithography

    Science.gov (United States)

    Tanabe, Akira; Uehara, Takuya; Nagase, Kazuro; Ikedo, Hiroaki; Hiroshiba, Nobuya; Nakamura, Takahiro; Nakagawa, Masaru

    2016-06-01

    We demonstrated a coating method of screen printing for discharging droplets of a high-viscosity resin on a substrate for ultraviolet (UV) nanoimprint lithography (NIL). Compared with a spin-coated resin film on a silicon substrate, discharged resin droplets on a silicon substrate were effective in terms of the uniformity of residual layer thickness (RLT) in contact with a mold with various pattern densities. Fluorescence microscope observations with a fluorescent-dye-containing UV-curable resin enabled the evaluation of the shapes of resin droplets discharged on a substrate surface. Widely used screen mesh plates composed of a stainless mesh covered with a patterned emulsion film caused defects of undischarged parts, whereas defects-free resin droplets with a narrow size distribution were discharged by mesh-free plates prepared with laser ablation. The pitch-to-diameter ratio in the configuration of 10-µm-diameter holes needs to be larger than 2.5 times for printing a resin having a viscosity of 12,800 mPa s.

  2. Induction of UV photoproducts and DNA damage by solar simulator UV irradiation

    International Nuclear Information System (INIS)

    Wolfreys, A.; Henderson, L.; Clingen, P.

    1997-01-01

    The recent increased incidence of skin cancer and the depletion of the ozone layer has increased interest in the ultraviolet (UV) component of natural sunlight and its role in the induction of skin cancer. Previous research on UV radiation has concentrated on UVC (254nm) but, as only UVB and UVA are present in natural sunlight, its relevance is unknown. We have investigated the induction of two forms of direct DNA damage - the pyrimidine dimer and the (6-4) photoproduct - in human DNA repair deficient XP-G (Xeroderma pigmentosum group G) lymphoblastoid cells following exposure to simulated sunlight. As exposure to natural sunlight is highly variable, a solar simulator lamp was used which is known to mimic natural sunlight at midday in Central Europe. Cells were irradiated on ice to minimise DNA repair and the relative induction of pyrimidine dimers and (6-4) photoproducts was measured using specific monoclonal antibodies and a computer assisted image analysis system. A time dependent increase in both cyclobutane dimer and (6-4) photoproduct antibody binding sites was seen. The increases in pyrimidine dimer and (6-4) photoproduct antibody binding sites differed to that reported with natural sunlight in the UK but was similar to that seen with a similar solar simulator lamp

  3. Two UV colours of the central part of M 31

    Science.gov (United States)

    Deharveng, J. M.; Laget, M.; Monnet, G.; Vuillemin, A.

    1976-01-01

    Two photographs of the galaxy M 31 have been obtained in the far UV with a Faust rocket experiment and in the near UV with the S 183 experiment aboard Skylab. Only the central part of the galaxy is detected. Reductions provide both the energy received and the angular area over M 31 from which it is emitted. The UV flux is brighter than expected from extrapolation of the visible spectrum. The distribution below 300 A is rather flat and different from previous OAO-2 observations. These results, combined with Lyman continuum flux evaluation, are used to discuss the temperature and the age of the stars which may be responsible for this anomalous UV distribution.

  4. Reverse-contact UV nanoimprint lithography for multilayered structure fabrication

    DEFF Research Database (Denmark)

    Kehagias, N.; Reboud, V.; Chansin, G.

    2007-01-01

    In this paper, we report results on a newly developed nanofabrication technique, namely reverse-contact UV nanoimprint lithography. This technique is a combination of nanoimprint lithography and contact printing lithography. In this process, a lift-off resist and a UV cross-linkable polymer...... are spin-coated successively onto a patterned UV mask-mould. These thin polymer films are then transferred from the mould to the substrate by contact at a suitable temperature and pressure. The whole assembly is then exposed to UV light. After separation of the mould and the substrate, the unexposed...... polymer areas are dissolved in a developer solution leaving behind the negative features of the original stamp. This method delivers resist pattern transfer without a residual layer, thereby rending unnecessary the etching steps typically needed in the imprint lithography techniques for three...

  5. Microbial raw data for UV-C LED disinfection study

    Data.gov (United States)

    U.S. Environmental Protection Agency — This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at...

  6. UV-inducible DNA repair in Acinetobacter calcoaceticus

    International Nuclear Information System (INIS)

    Berenstein, D.

    1987-01-01

    Bacterial mutation frequency after UV irradiation and phage mutation frequency under conditions of W-reactivation were determined in A. calcoaceticus. With the exception of streptomycin resistance, there was no increase in the frequency of the assayed markers above the background level. The increased survival of phage during W-reactivation was not followed by an increase in the frequency of mutation from turbid to clear plaque formers among phage survivors. The findings suggested that the UV-inducible repair pathway in A. calcoaceticus was error free. Post-irradiation incubation of UV-treated culture before phage infection resulted in a further increase of W-reactivation. As chloramphenicol inhibited this response, it was concluded that de novo protein synthesis was involved in the UV-inducible repair pathway in A. calcoaceticus. (Auth.)

  7. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J. (Queensland Univ., Brisbane (Australia))

    1982-05-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds.

  8. The inhibition of repair in UV irradiated human cells

    International Nuclear Information System (INIS)

    Collins, A.R.S.; Schor, S.L.; Johnson, R.T.

    1977-01-01

    Three different assay procedures are used to determine the effects of hydroxyurea on excision repair in UV-irradiated HeLa cells. At the cytological level, incubation of UV-irradiated metaphase cells with hydroxyurea caused chromosome decondensation. Using a modified alkaline sucrose gradient sedimentation technique involving minimal lysis before centrifugation, a marked retardation was found in the sedimentation of DNA from UV-irradiated cells incubated for a short period with hydroxyurea. The effect of hydroxyurea on the incorporation of [ 3 H]thymidine by UV-irradiated G1 cells was found to depend on the concentration of thymidine present in the medium. The results point to an inhibition of repair DNA synthesis by hydroxyurea (or deoxyadenosine), at the level of the supply of DNA precursors, i.e. in the same way that these agents inhibit semiconservative DNA synthesis. In the presence of these inhibitors, single-strand gaps accumulate in the DNA

  9. UV radiation and mouse models of herpes simplex virus infection

    International Nuclear Information System (INIS)

    Norval, Mary; El-Ghorr, A.A.

    1996-01-01

    Orolabial human infections with herpes simplex virus type 1 (HSV-1) are very common; following the primary epidermal infection, the virus is retained in a latent form in the trigeminal ganglia from where it can reactivate and cause a recrudescent lesion. Recrudescences are triggered by various stimuli including exposure to sunlight. In this review three categories of mouse models are used to examine the effects of UV irradiation on HSV infections: these are UV exposure prior to primary infection, UV exposure as a triggering event for recrudescence and UV exposure prior to challenge with virus is mice already immunized to HSV. In each of these models immunosuppression occurs, which is manifest, in some instances, in increased morbidity or an increased rate of recrudescence. Where known, the immunological mechanisms involved in the models are summarized and their relevance to human infections considered. (Author)

  10. Plasmid-mediated UV-protection in Streptococcus lactis

    Energy Technology Data Exchange (ETDEWEB)

    Chopin, M.C.; Rouault, A. (Institut National de la Recherche Agronomique, Rennes (France). Lab. de Recherches de Technologie Laitiere); Moillo-Batt, A. (Institut National de la Sante et de la Recherche Medicale (INSERM), Hopital de Pontchaillon, 35 - Rennes (France))

    1985-02-01

    Streptococcus lactis strain IL594 contains 9 plasmids, designated pIL1 to pIL9. On the basis of protoplast-induced curing experiments the authors showed that derivatives containing pIL7 were resistant to UV-irradiation while derivatives lacking pIL7 were sensitive. The pIL7-determined UV-protection was confirmed by co-transfer of the plasmid and of the character into a plasmid-free derivative of S. lactis IL594. Moreover, prophage induction required higher UV-fluence in this derivative carrying pIL7 than in the plasmid-free strain. This is the first report of a plasmid-mediated UV-protection in group N streptococci.

  11. Conformational Effects of UV Light on DNA Origami.

    Science.gov (United States)

    Chen, Haorong; Li, Ruixin; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

    2017-02-01

    The responses of DNA origami conformation to UV radiation of different wavelengths and doses are investigated. Short- and medium-wavelength UV light can cause photo-lesions in DNA origami. At moderate doses, the lesions do not cause any visible defects in the origami, nor do they significantly affect the hybridization capability. Instead, they help relieve the internal stress in the origami structure and restore it to the designed conformation. At high doses, staple dissociation increases which causes structural disintegration. Long-wavelength UV does not show any effect on origami conformation by itself. We show that this UV range can be used in conjunction with photoactive molecules for photo-reconfiguration, while avoiding any damage to the DNA structures.

  12. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    International Nuclear Information System (INIS)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J.

    1982-01-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds. (author)

  13. Silicon Microchannel Plate Large Area UV Detector, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA need for high-quantum-efficiency, high-resolution, low-cost photodetectors for the far-UV spectral range, Physical Optics Corporation (POC)...

  14. Intrinsic thermoluminescence of NaCl:Tl in UV dosimetry

    International Nuclear Information System (INIS)

    Barghare, S.P.; Joshi, R.V.; Joshi, T.R.; Kathuria, S.P.

    1982-01-01

    NaCl:Tl(T) phosphor is found to have high intrinsic thermoluminescence (TL) sensitivity to 253.7 nm UV-radiation. The dosimetric glow peak II grows sublinearly with increase in UV dose in the range 10 3 to 10 6 JM -2 . The other requirements of an efficient dosimeter material such as high storage stability, matching of the spectral response of detector tube and TL-emission from phosphor, reproducibility, desirable size and shape, easy availability in powder, pellet and crystal forms at cheaper rates, and repeated re-usability of the same phosphor without much difficulty, etc., are additional factors which strengthen the claim of NaCl:Tl(T) phosphor as UV dosimetric material. It is proposed that present NaCl:Tl(T) material is suitable TL-phosphor for UV dosimetry in the range 10 3 to 10 6 JM -2 . (author)

  15. Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Anhøj, Thomas Aarøe; Caviglia, Claudia

    2017-01-01

    In this work we present an easy, fast, reliable and low cost microfabrication technique for fabricating suspended microstructures of epoxy based photoresistswith UV photolithography. Two different fabrication processes with epoxy based resins (SU-8 and mr-DWL) using UV exposures at wavelengths...... of 313 nm and 405 nm were optimized and compared in terms of structural stability, control of suspended layer thickness and resolution limits. A novel fabrication process combining the two photoresists SU-8 and mr-DWL with two UV exposures at 365 nm and 405 nm respectively provided a wider processing...... window for definition of well-defined suspended microstructures with lateral dimensions down to 5 μmwhen compared to 313 nm or 365 nm UV photolithography processes....

  16. Studies of aluminium nitride ceramics for application in UV dosimetry

    DEFF Research Database (Denmark)

    Trinkler, L.; Bøtter-Jensen, L.; Christensen, P.

    2000-01-01

    The study is reported of the ceramic material AlN-Y2O3 as a potential luminescence dosemeter for the detection of UV radiation. Both the thermoluminescence and the optically stimulated luminescence properties of the material have been studied after exposure to UV radiation and compared with those...... of the widely used dosemeter material Al2O3:C. It has been shown that AlN-Y2O3 ceramics exhibit three orders of magnitude higher sensitivity to UV radiation than does Al2O3,:C over a broad spectral region. The thermoluminescence from AlN-Y2O3 is characterised by linear dose dependence over a wide range....... The fading characteristics of the UV-induced thermoluminescence and optically stimulated luminescence signals with storage time at room temperature were found to be a drawback, but still lower than those induced after exposure to ionising radiation....

  17. Biological and medical effects of UV radiation on human health

    International Nuclear Information System (INIS)

    Piazena, H.

    1994-01-01

    Effecsts of UV radiation on human health are discussed. UV radiation is taken up through the skin and eyes. In the case of the eyes, the only known effects are damaging ones (e.g. cataracts). Irradiation of the skin, on the other hand, may either have a prophylactic and therapeutic effect or cause health problems if the exposure is too frequent and/or the dose too high. Positive effects are: Stimulation of the vitamin-D-3 synthesis and the autoimmune system, economisation of blood circulation, higher fitness, and the development of a UV protection system in the skin. Negative effects are: UV erythema, disturbances of the unspecific resistance and the immune system, and photocarcinogenesis. (orig.) [de

  18. Study of induced functions by UV in Staphylococcus

    International Nuclear Information System (INIS)

    Silva, B.S. da.

    1982-01-01

    SOS functions induced by ultraviolet (UV) radiation were studied using S. aureus and S. epidermidis. Comparing the results obtained from these two organisms with those described in the literature for E. coli allows us to conclude: the difference in UV sensibility between the lysogenic and non-lysogenic strains of Staphylococcus is extremely large; the dose of UV radiation which results in the maximum induction of the lysogenic strains lead to 99% inactivation of the lysogenic strains; the kinetics of prophage liberation in lysogenic cultures of Staphylococcus is more rapid than those described for E. coli; the dose of UV radiation is much lower than the dose described for E. coli; the maximum W-reactivatio and W-mutagenesis are obtained immediately after the irradiation or within the 15 minutes allowed for the phage adsorption. (author)

  19. The near-UV absorber OSSO and its isomers.

    Science.gov (United States)

    Wu, Zhuang; Wan, Huabin; Xu, Jian; Lu, Bo; Lu, Yan; Eckhardt, André K; Schreiner, Peter R; Xie, Changjian; Guo, Hua; Zeng, Xiaoqing

    2018-05-01

    Disulfur dioxide, OSSO, has been proposed as the enigmatic "near-UV absorber" in the yellowish atmosphere of Venus. However, the fundamentally important spectroscopic properties and photochemistry of OSSO are scarcely documented. By either condensing gaseous SO or 266 laser photolysis of an S2O2 complex in Ar or N2 at 15 K, syn-OSSO, anti-OSSO, and cyclic OS([double bond, length as m-dash]O)S were identified by IR and UV/Vis spectroscopy for the first time. The observed absorptions (λmax) for OSSO at 517 and 390 nm coincide with the near-UV absorption (320-400 nm) found in the Venus clouds by photometric measurements with the Pioneer Venus orbiter. Subsequent UV light irradiation (365 nm) depletes syn-OSSO and anti-OSSO and yields a fourth isomer, syn-OSOS, with concomitant dissociation into SO2 and elemental sulfur.

  20. UV response on dielectric properties of nano nematic liquid crystal

    Directory of Open Access Journals (Sweden)

    Kamal Kumar Pandey

    2018-03-01

    Full Text Available In this work, we investigate the effect of UV light irradiation on the dielectric parameters of nematic liquid crystal (5CB and ZnO nanoparticles dispersed liquid crystal. With addition of nanoparticles in nematic LC are promising new materials for a variety of application in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however we optimize the properties of liquid crystal and understand how the UV light irradiation interact the nanoparticles and LC molecules in dispersed/doped LC. The dielectric permittivity and loss factor have discussed the pure nematic LC and dispersed/doped system after, during and before UV light exposure. The dielectric relaxation spectroscopy was carried out in the frequency range 100 Hz–10 MHz in the nematic mesophase range. Keywords: Dielectric permittivity, Relaxation frequency, Nematic liquid crystal, UV light irradiation

  1. UV Resonant Raman Spectrometer with Multi-Line Laser Excitation

    Science.gov (United States)

    Lambert, James L.; Kohel, James M.; Kirby, James P.; Morookian, John Michael; Pelletier, Michael J.

    2013-01-01

    A Raman spectrometer employs two or more UV (ultraviolet) laser wavel engths to generate UV resonant Raman (UVRR) spectra in organic sampl es. Resonant Raman scattering results when the laser excitation is n ear an electronic transition of a molecule, and the enhancement of R aman signals can be several orders of magnitude. In addition, the Ra man cross-section is inversely proportional to the fourth power of t he wavelength, so the UV Raman emission is increased by another fact or of 16, or greater, over visible Raman emissions. The Raman-scatter ed light is collected using a high-resolution broadband spectrograph . Further suppression of the Rayleigh-scattered laser light is provi ded by custom UV notch filters.

  2. Reverse-contact UV nanoimprint lithography for multilayered structure fabrication

    International Nuclear Information System (INIS)

    Kehagias, N; Reboud, V; Chansin, G; Zelsmann, M; Jeppesen, C; Schuster, C; Kubenz, M; Reuther, F; Gruetzner, G; Torres, C M Sotomayor

    2007-01-01

    In this paper, we report results on a newly developed nanofabrication technique, namely reverse-contact UV nanoimprint lithography. This technique is a combination of nanoimprint lithography and contact printing lithography. In this process, a lift-off resist and a UV cross-linkable polymer are spin-coated successively onto a patterned UV mask-mould. These thin polymer films are then transferred from the mould to the substrate by contact at a suitable temperature and pressure. The whole assembly is then exposed to UV light. After separation of the mould and the substrate, the unexposed polymer areas are dissolved in a developer solution leaving behind the negative features of the original stamp. This method delivers resist pattern transfer without a residual layer, thereby rending unnecessary the etching steps typically needed in the imprint lithography techniques for three-dimensional patterning. Three-dimensional woodpile-like structures were successfully fabricated with this new technique

  3. Plasmid-mediated UV-protection in Streptococcus lactis

    International Nuclear Information System (INIS)

    Chopin, M.-C.; Rouault, A.

    1985-01-01

    Streptococcus lactis strain IL594 contains 9 plasmids, designated pIL1 to pIL9. On the basis of protoplast-induced curing experiments the authors showed that derivatives containing pIL7 were resistant to UV-irradiation while derivatives lacking pIL7 were sensitive. The pIL7-determined UV-protection was confirmed by cotransfer of the plasmid and of the character into a plasmid-free derivative of S. lactis IL594. Moreover, prophage induction required higher UV-fluence in this derivative carrying pIL7 than in the plasmid-free strain. This is the first report of a plasmid-mediated UV-protection in group N streptococci. (orig.)

  4. UV Stellar Distribution Model for the Derivation of Payload

    Directory of Open Access Journals (Sweden)

    Young-Jun Choi

    1999-12-01

    Full Text Available We present the results of a model calculation of the stellar distribution in a UV and centered at 2175Å corresponding to the well-known bump in the interstellar extinction curve. The stellar distribution model used here is based on the Bahcall-Soneira galaxy model (1980. The source code for model calculation was designed by Brosch (1991 and modified to investigate various designing factors for UV satellite payload. The model predicts UV stellar densities in different sky directions, and its results are compared with the TD-1 star counts for a number of sky regions. From this study, we can determine the field of view, size of optics, angular resolution, and number of stars in one orbit. There will provide the basic constrains in designing a satellite payload for UV observations.

  5. UV Radiation in an Urban Canyon in Southeast Queensland

    Science.gov (United States)

    McKinley, A. R.; Moore, M. R.; Kimlin, M. G.

    2006-12-01

    Ultraviolet radiation (UV) has the possibility to both harm and to benefit human beings when unprotected exposure occurs. After receiving small amounts of UV our bodies begin to synthesise vitamin D, which is essential for maintaining healthy bones, however excessive UV exposure can result in a variety of damaging outcomes ranging from sunburn to skin cancer and cataracts. For this reason it is very important to understand the different environments in which people encounter UV so as to better prepare the public to make smart and healthy sun exposure decisions. Each day more and more people are moving into large cities around the world and spending their time inside the urban canyon, however UV measurements are generally taken at scientific stations in open areas or on top of tall buildings, meaning that at times the environmental characteristics measured may not accurately represent those found at street-level in these highly urbanized areas. Urban canyons are home to both very tall buildings and tropospheric air pollution, each of which reduces the amount of UV reaching street-level. This study measured the varying difference between UV measurements taken at street-level and at a standard UV monitoring site on top of a building outside of the urban canyon. Investigation was conducted in the central business district (CBD) of Brisbane, Australia, which models the CBDs of large cities around the world in that it boasts a great number of tall buildings, including many skyscrapers. Data was collected under clear sky conditions at five different street-level sites in the CBD (on either side of two streets running perpendicular to one another (four sites) and in a public square) and then compared to that obtained on the same day at the Queensland University of Technology's Australian Sun and Health Research Laboratory (ASHRL), which is located 2.5 kilometres outside Brisbane's CBD. Minimum erythemal dose (MED) data was collected at each location and it was found that

  6. Respiration shutoff in Escherichia coli after far-uv irradiation

    International Nuclear Information System (INIS)

    Swenson, P.A.; Norton, I.L.

    1984-01-01

    Damage to DNA of Escherichia coli by uv, ionizing radiation and chemicals causes a number of responses that require the recA + and lexA + gene products. The responses include error prone repair (as indicated by mutagenesis), filamentation and induction of prophage lambda. Another important rec/lex response, shutoff of respiration, which occurs 60 min after exposure to uv, is studied. Objective is to understand the genetic and biochemical bases of the shutoff process and its control

  7. Evaluating UV-C LED disinfection performance and ...

    Science.gov (United States)

    This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at inactivating Escherichia. coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores; research included an evaluation of genomic damage. Inactivation by the LEDs was compared with the efficacy of conventional UV sources, the low-pressure (LP) and medium-pressure (MP) mercury vapor lamps. The work also calculated the electrical energy per order of reduction of the microorganisms by the five UV sources.For E. coli, all five UV sources yielded similar inactivation rates. For MS2 coliphage, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was significantly more effective than the LP UV and UVC LED sources. When considering electrical energy per order of reduction, the LP UV lamp was the most efficient for E. coli and MS2, and the MPUV and LPUV were equally efficient for HAdV2 and B. pumilus spores. Among the UVC LEDs, the 280 nm LED unit required the least energy per log reduction of E. coli and HAdV2. The 280 nm and 260|280 nm LED units were equally efficient per log reduction of B. pumilus spores, and the 260 nm LED unit required the lowest energy per order of reduction of MS2 coliphage. The combination of the 260 nm and 280 nm UV LED wavelengths was also evaluated for potential synergistic effects. No dual-wavelength synergy was detected for inactivation of

  8. Cellular repair and its importance for UV-induced mutations

    Energy Technology Data Exchange (ETDEWEB)

    Slamenova, D [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Vyskumny Ustav Onkologicky

    1975-01-01

    Current knowledge is briefly surveyed of the mechanism of the biological repair of injuries induced in DNA cells by the action of various factors, mainly ultraviolet radiation. Genetic loci determining the sensitivity of cells to UV radiation are defined and principal reparation processes are explained; excision repair is described more fully. The role of biological repair is discussed in view of UV-induced mutations in DNA cells.

  9. Direct UV-written broadband directional broadband planar waveguide couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation.......We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation....

  10. Evaluation of Combined Peracetic acid and UV treatment for ...

    Science.gov (United States)

    The current study evaluates the effectiveness of the combined application of Peracetic acid and ultraviolet radiation as alternative disinfectant agents to the traditional chlorination of wastewater effluents. Various pathogens (E. coli, enterococci and fecal coliforms) were evaluated in the study. Four experiments were conducted using low to high PAA levels and UV dosages. E. coli and enterococci were resistant to low to moderate PAA dosage (0.5- 1 mg/L). These microbes can be removed effectively at high PAA dosage (2.5 mg/L) with 30 min contact time. Fecal coliforms were completely inactivated even at a low PAA dose of 0.7 mg/L. E. coli was more susceptible to UV disinfection than enterococci at low UV dosages. Enterococci required at least 40 mJ/cm2 for 2.5 log inactivation. In combined PAA + UV treatment, low UV intensities between 7 – 40 mJ/cm2 showed poor disinfection performance at a low PAA concentration of 1.5 mg/L. High UV intensities of 120 and 60 mJ/cm2 inactivated all the pathogens to below detection levels even at low to moderate PAA (0.7 mg/L and 1 mg/L) pretreatment concentration. Combined PAA + UV treatment at 1 mg/L (for 15 and 30 min contact time) + 120 and 60 mJ/cm2 did not show any regrowth of microbes, whereas PAA only disinfection with 15 min contact time showed regrowth of enterococci and fecal coliforms. UV only disinfection showed E. coli regrowth. • This pilot scale study was designed for providing necessary parameter optimization

  11. UV and EB radiation processing in developing countries

    International Nuclear Information System (INIS)

    Garnett, J.L.

    1991-01-01

    Ultraviolet and electron beams (EB) are to be considered as complementary technologies in the radiation processing field. In many countries, UV processing is used as the pathfinder for EB. In the developing countries the decision to adopt radiation processing techniques to choose between UV and EB will largely be determined by economics, the availability of the chemists and also skilled personnel to service both lines and equipment. (orig./A.B.)

  12. Flare activity on UV Ceti: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-01-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  13. Characterization of UV written waveguides with luminescence microscopy

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Rosbirk, Tue

    2005-01-01

    Luminescence microscopy is used to measure the refractive index profile and molecular defect distribution of UV written waveguides with a spatial resolution of ~0.4 mm and high signal-to-noise ratio. The measurements reveal comlex waveguide formation dynamics with significant topological changes...... in the core profile. In addition, it is observed that thewaveguide formation process requires several milliseconds of UV exposure before starting....

  14. Utilising shade to optimize UV exposure for vitamin D

    Science.gov (United States)

    Turnbull, D. J.; Parisi, A. V.

    2008-06-01

    Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50° can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

  15. Flare activity on UV CETI: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-06-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  16. LASER PROCESSING ON SINGLE CRYSTALS BY UV PULSE LASER

    OpenAIRE

    龍見, 雅美; 佐々木, 徹; 高山, 恭宜

    2009-01-01

    Laser processing by using UV pulsed laser was carried out on single crystal such as sapphire and diamond in order to understand the fundamental laser processing on single crystal. The absorption edges of diamond and sapphire are longer and shorter than the wave length of UV laser, respectively. The processed regions by laser with near threshold power of processing show quite different state in each crystal.

  17. Conformation of L-Tyrosine Studied by Fluorescence-Detected UV-UV and IR-UV Double-Resonance Spectroscopy

    OpenAIRE

    Inokuchi, Yoshiya; Kobayashi, Yusuke; Ito, Takafumi; Ebata, Takayuki

    2007-01-01

    The laser-induced fluorescence spectrum of jet-cooled L-tyrosine exhibits more than 20 vibronic bands in the 35450-35750 cm-1 region. We attribute these bands to eight conformers by using results of UV-UV hole-burning spectroscopy. These isomers are classified into four groups; each group consists of two rotational isomers that have a similar side-chain conformation but different orientations of the phenolic OH. The splitting of band origins of rotational isomers is 31, 21, 5, and 0 cm-1 for ...

  18. The Global Solar UV Index used in the United Kingdom

    International Nuclear Information System (INIS)

    New, C.; Driscoll, C.M.H.; Kitchen, K.; Miners, B.

    2000-01-01

    Weather forecast bulletins on television, radio and in the newspapers in the UK now include advice about the strength of the ultraviolet (UV) radiation from the sun in terms of the Global Solar UV Index. A numerical scale of 1 to 20 is used to quote the Index for anywhere in the world and the Index addresses all ethnic groups. The Index replaces the sunburn warning system. The daily UV Index is calculated by the Met. Office from documented UV radiation levels and current atmospheric data and takes into account cloud cover forecast. Armed with the knowledge of the UV Index the public will be able to assess their personal risk of sun damage at home or abroad depending on their natural skin colour. Four categories of skin colour are identified with the Index; white skin that sunburns easily, white skin that tans readily, brown skin and black skin. A colour-coded rating from low to very high is used to identify personal risk with these skin colour categories. The Global UV Index forms an important part of the 'Sun Safety Code' developed by health organisations within the UK. (author)

  19. The regrowth of phytoplankton cultures after UV disinfection

    International Nuclear Information System (INIS)

    Martínez, Lucía F.; Mahamud, Manuel M.; Lavín, Antonio G.; Bueno, Julio L.

    2013-01-01

    Highlights: ► Phytoplankton cultures were placed in a rich medium after UV-C irradiation. ► Flow cytometry and PAM were used for determining cell viability. ► The behavior differs from that of cultures kept in their original environment. ► Chlorella autotrophica recovers between 5 and 10 days after the treatment. ► Phaeocystis globosa shows only a slight recovery for low-dose UV-radiation exposure. - Abstract: This study addresses how cultures of three phytoplankton species –Chaetoceros calcitrans, Chlorella autotrophica and Phaeocystis globosa – can recover from the effects of UV-C exposure if the cells are placed in a rich medium. Flow cytometry and pulse amplitude modulation (PAM) were used to determine cell recovery after UV treatment. The recovery of C. calcitrans was complete 9 days after treatment. For C. autotrophica, the recovery was noticeable 5 days after treatment. P. globosa only recovered if the UV dose did not exceed 7.3 × 10 5 μWs/cm 2 . The recovery of the UV-treated cultures introduced to a regrowth medium, compared with the recovery of the irradiated cultures kept in their original environment, had two main characteristics: cell recovery was slower but was more efficient. This pattern of recovery has very important implications for real ballast water management systems because such systems discharge treated water into the environment

  20. Reduction of patulin in apple cider by UV radiation.

    Science.gov (United States)

    Dong, Qingfang; Manns, David C; Feng, Guoping; Yue, Tianli; Churey, John J; Worobo, Randy W

    2010-01-01

    The presence of the mycotoxin patulin in processed apple juice and cider presents a continual challenge to the food industry as both consumer health and product quality issues. Although several methods for control and/or elimination of patulin have been proposed, no unifying method has been commercially successful for reducing patulin burdens while maintaining product quality. In the present study, exposure to germicidal UV radiation was evaluated as a possible commercially viable alternative for the reduction and possible elimination of the patulin mycotoxin in fresh apple cider. UV exposure of 14.2 to 99.4 mJ/cm(2) resulted in a significant and nearly linear decrease in patulin levels while producing no quantifiable changes in the chemical composition (i.e., pH, Brix, and total acids) or organoleptic properties of the cider. For the range of UV doses tested, patulin levels decreased by 9.4 to 43.4%; the greatest reduction was achieved after less than 15 s of UV exposure. The method of UV radiation (the CiderSure 3500 system) is an easily implemented, high-throughput, and cost-effective method that offers simultaneous UV pasteurization of cider and juice products and reduction and/or elimination of patulin without unwanted alterations in the final product.