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Sample records for fluorescence induite par

  1. Kerosene detection using laser induced fluorescence imaging for aeronautical engines application; Detection du kerozene par imagerie de fluorescence induite par laser, pour application sur foyer aeronautique

    Energy Technology Data Exchange (ETDEWEB)

    Baranger, Ph.

    2004-10-15

    The new concepts of aeronautical engines, developed to follow the evolution of the European standards of pollution, are generally based on an improvement of the processes of liquid fuel injection and mixture in the combustion chamber. There is currently no model mature enough to work without experimental validation. The purpose of this thesis is to assess the possibility of measuring the kerosene (Jet A1) vapour distribution by PLIF (Planar Laser Induced Fluorescence). That measurement technique must quantitatively image the instantaneous concentrations fields of the vaporized fuel in a spray. The implementation of such a technique needs an experimental spectroscopic study, which was realized on the vapour of fuel. First of all, this study allowed us to determine the properties of the kerosene fluorescence spectrum versus physical parameters such as temperature, pressure or gas mixture composition, especially in presence of oxygen molecules. Then, it was shown that the fluorescence spectrum of the fuel could be reproduce in all physical conditions by a single mixture of four aromatics. Their photophysical properties were also analyzed. Following this spectroscopic study, a phenomenological model for the fluorescence of the gaseous fuel was set up. This model led us to a protocol for an optical diagnostic on this fuel vapour. An experiment was set up to test the implementation and the limits of this technique in simple laboratory conditions. This experiment confirmed that this is indeed a promising technique for the diagnostic of the fuel vapour in aeronautical engine. (author)

  2. Application of the laser induced fluorescence to the investigation of highly magnetized plasmas, heated by ion cyclotron resonance; Fluorescence induite par laser sur des plasmas fortement magnetises, chauffes par resonnance cyclotron ionique

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    1997-12-31

    This work has been achieved in the frame of isotopic separation studies by in cyclotron resonance. For this purpose, in a highly magnetized (2 to 3 Tesla) and non-collisional (10{sup 12} ions/cm{sup 3}) plasma, composed of metallic ions, a wave near the ion cyclotron frequency is thrown in order to heat selectively a given species. A laser induced fluorescence (LIP) has been developed on barium and gadolinium plasmas. The Larmor gyration of ions greatly modifies the interaction, which has been modelled through the time-dependent Schroedinger equation. The obtained excitation probably has been integrated over all the ions excited in the measurement volume in order to check that the LIF still leads to the distribution function of ion velocities. The influence of the Larmor motion of ions on the spectral distribution of LIF has been derived both theoretically and experimentally. The LIF diagnostics has been achieved with a dye O`ring laser. The barium ion has been excited on the transition 6142 angstrom, using rhodamine 6G dye, and the gadolinium ion on the pseudo-triplet 3861 angstrom, using exalite dye. Data treatment has been developed taking into account the Zeeman effect and the different heating of isotopes. The ionic temperature (from 1 eV to some hundreds eV) has been measured as a function of radiofrequency heating. Our experimental results are in good agreement with the selective heating theory. Also, the ion velocity distribution function has been found locally Maxwellian. And the behaviour of the plasma has been studied as a function of control parameters of the plasma source. (author) 62 refs.

  3. Priapisme induit par la chlorpromazine: A propos de deux cas

    Directory of Open Access Journals (Sweden)

    I. Marrag

    2016-06-01

    Le priapisme veineux est une urgence urologique. Il constitue un des effets secondaires des neuroleptiques parmi les quels la chlorpromazine. Cet effet iatrogène, qui est rare mais grave, doit être connu par les cliniciens afin d’être mieux prévenu pour éviter les séquelles érectiles.

  4. Douleurs induites par les soins: la réalité au Centre Hospitalier Universitaire de Befelatanana Antananarivo, Madagascar

    Science.gov (United States)

    Mahavivola, Ernestho-Ghoud Indretsy; Olivah, Razanaparany Miarisoa Mireille; Mihary, Dodo; Hendriniaina, Rakotoharivelo; Lalao, Randriamboavonjy Rado; Henintsoa, Rakotonirainy Oliva; Fahafahantsoa, Rapelanoro Rabenja

    2014-01-01

    La douleur induite par les soins correspond à la douleur survenant lors des actes à visé diagnostique et/ou thérapeutique. A notre connaissance, nous n'avons pas encore des données disponibles pour les douleurs induites par les soins à l'Hôpital de Befelatanana. Nos objectifs étaient de décrire le profil épidémiologique de la douleur induite par les soins, d'identifier les principaux facteurs influençant sur l'intensité de la douleur et leurs retentissements chez les patients. Il s'agissait d'une étude rétrospective, transversale type un jour donné menée dans les douze services de Médecines au Centre Hospitalier Universitaire de Befelatanana en Novembre 2013. Cent deux patients ont été retenus dans l’étude et trois cent vingt trois actes douloureux étaient enregistrés. La fréquence de la douleur induite par les soins était de 69,86%. Le genre féminin prédominait dans 52% des cas (n = 53) avec un sex-ratio à 0,92. L’âge moyen était de 46 ans. Les ponctions vasculaires étaient l'acte prédominant dans 49,54% (n = 109) des cas. Les infirmiers réalisaient les soins dans 47,05% (n = 48) des cas. L'information verbale était la mesure préventive utilisée dans 57,84% des cas (n = 59). Le transport par marche à pied et au dos représentait 16,67% des cas (n = 17). Les patients naïfs des gestes étaient plus anxieux. Ces patients gardaient de mauvais souvenir dans 64,71% des cas (n = 66). La fréquence de douleur induite par les soins était trop élevée. Un effort important est nécessaire pour réduire la douleur induite par les soins PMID:25932071

  5. Protection des ions organiques contre les dommages induits a l'ADN par les electrons de basse energie

    Science.gov (United States)

    Dumont, Ariane

    Il a ete demontre que les electrons de basse energie (EBE) peuvent induire des cassures simple brin (CSB) a l'ADN, via la formation d'anions transitoires qui decroissent par attachement dissociatif, ou dans d'autres etats electroniques dissociatifs menant a la fragmentation. Afin d'effectuer une etude complete des effets des electrons de basse energie sur la matiere biologique, il est necessaire de comprendre leur mecanismes d'interaction non seulement avec l'ADN, mais avec les constituants de son environnement. Les histones sont une composante importante de l'environnement moleculaire de l'ADN. Leur charge positive leur permet de s'associer aux groupements phosphate anionique de l'ADN. Le role principal de ces proteines basiques consiste a organiser l'ADN et l'empaqueter afin de former la chromatine. Les cations sont une autre composante importante de la cellule; ils jouent un role dans la stabilisation de la conformation B de l'ADN in vitro par leurs interactions avec les petits et grands sillons de l'ADN, ainsi qu'avec le groupement phosphate charge negativement. Avec les histones, ils participent egalement a la compaction de l'ADN pour former la chromatine. Cette etude a pour but de comprendre comment la presence d'ions organiques (sous forme de Tris et d'EDTA) a proximite de l'ADN modifie le rendement de cassures simple brin induit par les electrons de basse energie. Le Tris et l'EDTA ont-ete choisis comme objet d'etude, puisqu'en solution, ils forment le tampon standard pour solubiliser l'ADN dans les experiences in vitro (10mM Tris, 1mM EDTA). De plus, la molecule Tris possede un groupement amine alors que l'EDTA possede 4 groupements carboxyliques. Ensembles, ils peuvent se comporter comme un modele simple pour les acides amines. Le ratio molaire de 10 :1 de Tris par rapport a l'EDTA a pour but d'imiter le comportement des histones qui sont riches en arginine et lysine, acides amines possedant un groupement amine charge positivement additionnel. Des films d

  6. Influence des conditions initiales sur l'évolution d'une onde de choc induite par impulsion laser

    OpenAIRE

    Cottet , F.; Romain , J.P.

    1983-01-01

    L'évolution d'un choc de forte amplitude induit par une impulsion laser dans une cible solide est décrite à l'aide d'un modèle hydrodynamique, précisant un modèle antérieur par la prise en compte du déplacement de la surface avant de la cible sous l'effet de la pression d'ablation. Ce modèle est également utilisé pour étudier l'influence du profil initial de pression sur l'amortissement de l'onde de choc au cours de sa propagation.

  7. Réponse au stress induit par le transport chez la truite arc-en-ciel (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    ROUGER Y.

    1998-07-01

    Full Text Available La réponse au stress induit par le transport a été étudiée chez des truites arc-en-ciel immatures d'un poids moyen de 200 g. D'une manière globale, les valeurs de l'hématocrite, de l'osmolarité du plasma sanguin, du Cortisol et de la testostérone sont significativement plus élevées chez les poissons transportés que chez les témoins non transportés, alors que les niveaux de gonadostimuline (GTH1 et d'hormone de croissance ne diffèrent pas suivant les lots. L'analyse du comportement en "open field" des individus de chaque lot montre que les poissons transportés s'immobilisent en moyenne après un temps significativement plus long que les témoins. L'étude des performances zootechniques de chaque lot pendant les deux mois suivant l'expérience indique que le lot transporté récupère rapidement.

  8. Experimental study of superconductivity induced by proximity effects; Etude experimentale de la supraconductivite induite par effets de proximite

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-11-15

    We present a study of the proximity effects between a superconductor (InBi or PbBi alloys) and a 'normal' metal (Zn or Sn respectively, above their critical temperature) using essentially the tunneling techniques. On the N side, some specific properties of such an induced superconductivity are described: linear variation of the pair potential near the critical temperature of the binary layer, T{sub CNS}; reduced energy scale at T{sub CNS}; evidence of a thermodynamic critical field (called breakdown field) presented by N above its critical temperature. On the S side, we study crossing from a gapless to a quasi gapless regime. This gives a proof of a finite coherence length at T{sub CNS}. Experimental details (in particular about the preparation and measurement of tunneling junctions) are given in annexe. Possible applications are suggested. (author) [French] Nous presentons une etude experimentale des effets de proximite entre un supraconducteur (alliages d'InBi ou de PbBi) et un metal 'normal' (Zn ou Sn respectivement, pris au-dessus de leur temperature critique), en utilisant principalement des mesures d'effet tunnel. Du cote N, on met en evidence des proprietes specifiques de cette supraconductivite induite: comportement lineaire du potentiel de paires pres de la temperature critique du bilame, T{sub CNS}; echelle d'energie reduite a T{sub CNS}; apparition d'un champ critique thermodynamique (appele champ de basculement) dans N au-dessus de sa temperature critique. Du cote S, nous etudions le passage continu d'une situation 'sans bande interdite' a basse temperature et en champ fort, a une situation 'pratiquement sans bande interdite' pres de T{sub CNS} en champ nul. Ceci fournit une preuve de la non divergence de la longueur de coherence a T{sub CNS}. Les techniques experimentales (et en particulier la preparation et la mesure de jonctions tunnel) sont decrites en detail dans une annexe. On envisage des applications pratiques possibles. (auteur)

  9. Étude des interactions hadroniques à deux corps chargés, induites sur des protons par un faisceau de $\\pi^{-}, K^{-}$, et $\\overline{p}$ entre 3 et 12 GeV/c, avec un angle de diffusion dans le centre de masse voisin de 90$^{o}$

    CERN Document Server

    Billoir, Pierre

    1983-01-01

    Étude des interactions hadroniques à deux corps chargés, induites sur des protons par un faisceau de $\\pi^{-}, K^{-}$, et $\\overline{p}$ entre 3 et 12 GeV/c, avec un angle de diffusion dans le centre de masse voisin de 90$^{o}$

  10. ETUDE DE L'EFFET DE QUELQUES FACTEURS SUR LA CYTOTOXICITE INDUITE PAR L'AMPHOTERICINE B ASSOCIEE AUX LIPOPROTEINES DU SERUM SANGUIN CHEZ DES CELLULES DE GLOBULES ROUGES HUMAINES

    OpenAIRE

    BOUCHERIT, ATMANI Zahia

    2014-01-01

    toxiques. Dans le cadre de l'élaboration d'une stratégie de développement de cette molécule visant à augmenter l'index thérapeutique tout en réduisant la toxicité, nous avons étudié l'effet de quelques facteurs sur la cytotoxicité induite par l'amphotéricine B associée à des lipoprotéines du sérum sanguin chez le globule rouge humain (modèle universel de cellules animales supérieures). Dans notre travail nous avons abordé d'une part, les effets des caractéristiques des lipoprot...

  11. Technique de la membrane induite pour la reconstruction des pertes ...

    African Journals Online (AJOL)

    humérus par la technique de la membrane induite au moyen d'une fibula non vascularisée avec apport de substitut osseux complémentaire chez une adolescente de 14 ans. Un incident cicatriciel a été observé sur le site de prélèvement.

  12. Numerical analysis of resonances induced by s wave neutrons in transmission time-of-flight experiments with a computer IBM 7094 II; Methodes d'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol et automatisation de ces methodes sur ordinateur IBM 7094 II

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-01-01

    Numerical analysis of transmission resonances induced by s wave neutrons in time-of-flight experiments can be achieved in a fairly automatic way on an IBM 7094/II computer. The involved computations are carried out following a four step scheme: 1 - experimental raw data are processed to obtain the resonant transmissions, 2 - values of experimental quantities for each resonance are derived from the above transmissions, 3 - resonance parameters are determined using a least square method to solve the over determined system obtained by equalling theoretical functions to the correspondent experimental values. Four analysis methods are gathered in the same code, 4 - graphical control of the results is performed. (author) [French] L'automatisation, sur ordinateur IBM 7094/II, de l'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol a ete accomplie en la decomposant selon un schema articule en quatre phases: 1 - le traitement des donnees experimentales brutes pour obtenir les transmissions interfero-resonnantes, 2 - la determination des grandeurs d'analyse a partir des transmissions precedentes, 3 - l'analyse proprement dite des resonances dont les parametres sont obtenus par la resolution d'un systeme surabondant. Quatre methodes d'analyse sont groupees en un meme programme, 4 - la procedure de verification graphique. (auteur)

  13. Numerical analysis of resonances induced by s wave neutrons in transmission time-of-flight experiments with a computer IBM 7094 II; Methodes d'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol et automatisation de ces methodes sur ordinateur IBM 7094 II

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-01-01

    Numerical analysis of transmission resonances induced by s wave neutrons in time-of-flight experiments can be achieved in a fairly automatic way on an IBM 7094/II computer. The involved computations are carried out following a four step scheme: 1 - experimental raw data are processed to obtain the resonant transmissions, 2 - values of experimental quantities for each resonance are derived from the above transmissions, 3 - resonance parameters are determined using a least square method to solve the over determined system obtained by equalling theoretical functions to the correspondent experimental values. Four analysis methods are gathered in the same code, 4 - graphical control of the results is performed. (author) [French] L'automatisation, sur ordinateur IBM 7094/II, de l'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol a ete accomplie en la decomposant selon un schema articule en quatre phases: 1 - le traitement des donnees experimentales brutes pour obtenir les transmissions interfero-resonnantes, 2 - la determination des grandeurs d'analyse a partir des transmissions precedentes, 3 - l'analyse proprement dite des resonances dont les parametres sont obtenus par la resolution d'un systeme surabondant. Quatre methodes d'analyse sont groupees en un meme programme, 4 - la procedure de verification graphique. (auteur)

  14. Alimentation animale et valeur nutritionnelle induite sur les produits dérivés consommés par l’homme : Les lipides sont-ils principalement concernés ?

    Directory of Open Access Journals (Sweden)

    Bourre Jean-Marie

    2003-09-01

    Full Text Available Dans quelle mesure la nourriture reçue par les animaux induit-elle une modification (amélioration ou au contraire dégradation de la valeur nutritionnelle des aliments qui en sont issus pour la nourriture de l’homme ? La réponse à cette question varie selon la nature des nutriments (vitamines, minéraux, acides gras poly-insaturés indispensables des graisses, acides aminés indispensables des protéines, et aussi de l’espèce considérée. Le problème est de rechercher l’impact réel des formulations des rations utilisées dans les élevages sur la valeur nutritionnelle des produits (viandes, lait et laitages, fromages et œufs, etc., et donc leur influence sur la santé du consommateur, évidemment dans un sens favorable. Les acides gras poly-insaturés oméga-3 (ω3 bénéficient de deux grands axes de valorisation. Le premier réside dans leur importance quantitative et leurs rôles dans le cadre de la mise en place et du maintien de divers organes, le cerveau au premier chef. Le second se trouve dans la prévention de diverses pathologies, les maladies cardio-vasculaires occupant une place prépondérante \\; avec, depuis peu, les maladies neuro-psychiatriques, stress, dépression et démence. Compte tenu des implications en termes de maladies, cardio-cérébro-vasculaires entre autres, le contrôle de la nature des acides gras constitutifs des graisses représente donc un enjeu considérable en ce qui concerne les viandes issues d’animaux terrestres, maritimes et aériens, du lait, des laitages, fromages et des œufs. Car la qualité des graisses données en nourriture animale détermine fondamentalement la valeur nutritionnelle des aliments qui en sont dérivés, pour la consommation humaine. Bien évidemment, il est relativement difficile de modifier la composition en acides gras des phospholipides constitutifs des membranes biologiques intégrées dans la multitude de types cellulaires, dont la spécificité est largement

  15. Utilisation de l'essai comete et du biomarqueur gamma-H2AX pour detecter les dommages induits a l'ADN cellulaire par le 5-bromodeoxyuridine post-irradiation

    Science.gov (United States)

    La Madeleine, Carole

    Ce memoire est presente a la Faculte de medecine et des sciences de la sante de l'Universite de Sherbrooke en vue de l'obtention du grade de maitre es sciences (M.Sc.) en radiobiologie (2009). Un jury a revise les informations contenues dans ce memoire. Il etait compose de professeurs de la Faculte de medecine et des sciences de la sante soit : Darel Hunting PhD, directeur de recherche (departement de medecine nucleaire et radiobiologie), Leon Sanche PhD, directeur de recherche (departement de medecine nucleaire et radiobiologie), Richard Wagner PhD, membre du programme (departement de medecine nucleaire et radiobiologie) et Guylain Boissonneault PhD, membre exterieur au programme (departement de biochimie). Le 5-bromodeoxyuridine (BrdU), un analogue halogene de la thymidine reconnu depuis les annees 60 comme etant un excellent radiosensibilisateur. L'hypothese la plus repandue au sujet de l'effet radio sensibilisant du BrdU est qu'il augmente le nombre de cassures simple et double brin lorsqu'il est incorpore dans l'ADN de la cellule et expose aux radiations ionisantes. Toutefois, de nouvelles recherches semblent remettre en question les observations precedentes. Ces dernieres etudes ont confirme que le BrdU est un bon radiosensibilisateur, car il augmente les dommages radio-induits dans l'ADN. Mais, c'est en etant incorpore dans une region simple brin que le BrdU radiosensibilise l'ADN. Ces recherches ont egalement revele pour la premiere fois un nouveau type de dommages produits lors de l'irradiation de l'ADN contenant du BrdU : les dimeres interbrins. Le but de ces travaux de recherche est de determiner si la presence de bromodeoxyuridine dans l'ADN augmente l'induction de bris simple et / ou double brin chez les cellules irradiees en utilisant de nouvelles techniques plus sensibles et specifiques que celles utilisees auparavant. Pour ce faire, les essais cometes et la detection des foci H2AX phosphorylee pourraient permettre d'etablir les effets engendres par

  16. Étude des matrices sol-gel en film mince par détection de molécule unique en champ large : diffusion moléculaire et agrégation photo-induite

    Science.gov (United States)

    Nutarelli, D.; Débarre, A.; Jaffiol, R.; Julien, C.; Richard, A.; Tchénio, P.; Chaput, F.; Boilot, J. P.

    2004-11-01

    La fluorescence de molécules de colorant dans des matrices sol-gel en film mince a été étudiée par détection de molécule unique. Outre les phénomènes de photo-blanchiment et de clignotement, un processus de photo-agrégation a été observé. Ce phénomène, dont la dynamique dépend de la présence d'oxygène, de l'intensité du laser d'excitation et de la température, montre l'existence de deux classes de molécules dans l'échantillon. Des molécules immobiles et d'autres qui diffusent. L'analyse de la dynamique d'agrégation permettra de dégager certaines caractéristiques du mécanisme de photo-agrégation et d'appréhender le rôle joué par la matrice sol-gel dans ce processus.

  17. Priapisme induit par la chlorpromazine: A propos de deux cas

    African Journals Online (AJOL)

    I. Marrag

    We report here two cases of priapism associated with chlorpromazine. The first one ... who was admitted for a manic episode in the context of bipolar disorder. The second ... comportement à type d'hétéroagressivité verbale et physique envers.

  18. uPAR-targeted optical near-infrared (NIR) fluorescence imaging and PET for image-guided surgery in head and neck cancer

    DEFF Research Database (Denmark)

    Christensen, Anders; Juhl, Karina; Persson, Morten

    2017-01-01

    . Histological analysis showed co-localization of the fluorescent signal, uPAR expression and tumor deposits. In addition, the feasibility of uPARguided robotic cancer surgery was demonstrated. Also, uPAR-PET imaging showed a clear and localized signal in the tongue tumors. Conclusions: This study demonstrated...

  19. Le diagnostic anténatal de la trisomie 21 par l'hybridation in situ en fluorescence (FISH): à propos des premiers tests réalisés au Maroc

    Science.gov (United States)

    Lamzouri, Afaf; Natiq, Abdelhafid; Tajir, Mariam; Sendid, Mohamed; Sefiani, Abdelaziz

    2012-01-01

    Introduction Le but de cette étude était de présenter les premiers résultats de diagnostic anténatal de la trisomie 21 par la technique d'hybridation in situ en fluorescence (FISH) au Maroc et discuter son intérêt dans le diagnostic rapide de cette aneuploïdie. Méthodes Ce travail a été réalisé chez 23 femmes avec des grossesses à haut risque de trisomie 21. La moyenne d’âge des gestantes étaient de 37,43 ans avec des extrêmes de 21 et 43 ans. Toutes étaient musulmanes mariées, mariage légitimé par la Charia, dont trois mariages consanguins, sauf une originaire de la République Démocratique du Congo qui était chrétienne et concubine. La majorité des femmes étaient fonctionnaires et avaient un niveau de scolarisation moyen à élevé. Toutes les patientes ont bénéficié d'une consultation de génétique médicale au cours de laquelle il leur a été donné des informations sur la technique, son intérêt et ses limites. Il s'agit de femmes enceintes qui avaient soit un âge maternel élevé ou des signes d'appel échographiques et/ ou biochimiques. Une des patientes était porteuse d'une translocation robertsonienne t(14;21) équilibrée. Une amniocentèse a été réalisée chez toutes les gestantes et aucun avortement n'a était induit par ce geste invasif. L’âge gestationnel moyen à la première consultation était de 14 semaines d'aménorrhée (SA) et à l'amniocentèse était de 16 SA et 5 jours. L'analyse FISH a été réalisée, après consentement des couples, sur des cellules non cultivées à partir des échantillons de liquides amniotiques, en utilisant des sondes spécifiques du chromosome 21. Résultats Parmi les 23 patientes qui ont bénéficiées d'un diagnostic anténatal de la trisomie 21 par la technique FISH, nous avons pu rassurer 21 d'entre elles, et nous avons détecté deux cas de trisomie 21 fœtal. Conclusion La technique FISH permet un diagnostic anténatal rapide, en moins de 48h, de la trisomie 21 sur

  20. Comparative Studies of Chemical Effects following Nuclear Reactions and Transformations on Metal Organic Phenyl Compounds; Etudes Comparatives des Effets Chimiques Induits par les Reactions et les Transformations Nucleaires sur des Composes Phenylmetalliques; 0421 0420 0410 0414 ; Estudios Comparativos de los Efectos Quimicos de las Reacciones y Transformaciones Nucleares en Compuestos Fenil-Organometalicos

    Energy Technology Data Exchange (ETDEWEB)

    Merz, E.; Riedel, H. J. [Kernforschungsanlage, Juelich, Federal Republic of Germany (Germany)

    1965-04-15

    concerne non seulement la categorie de produits typiques, mais aussi les rendements en pourcentage. Ainsi, les auteurs ont trouve, apres les reactions nucleaires sur le tetraphenylgermanium, plusieurs produits de recul de Ge et de Ga a caractere organometallique qu'il n'etait pas possible de deceler apres le processus de capture K dans le tetraphenylgermanium-{sup 68}Ge. La decroissance {beta}{sup -} dans le tetraphenylgermanium-{sup 77}Ge produit pratiquement les memes composes chimiques que ceux que l'on observe a la suite des reactions nucleaires. Toutefois, une augmentation notable de la fraction molecules generatrices marquees (retention) est typique de la transition {beta}{sup -}. Les resultats sont etudies a la lumiere de considerations theoriques sur la quantite d'energie cinetique transferee par le recul nucleaire a la molecule en reaction et l'excitation qui en resulte. Les auteurs emettent l'hypothese que le genre et la quantite de certaines nouvelles especes radioactives produites lors des evenements nucleaires sont fonction moins de la nature et de la concentration des fragments de recul primaires que des ions, des radicaux et des defauts de reseau induits dans les matieres irradiees par les effets de recul secondaires (interactions elastiques et inelastiques) , y compris l'influence particuliere de l'oxygene. (author) [Spanish] Los autores estudiaron los efectos quimicos producidos por atomos de retroceso de gran energia procedentes de reacciones nucleares en solidos y liquidos basandose en una amplia comparacion de los productos formados por los procesos (n, {gamma}) y (n,2n) en los compuestos fenilmetalicos de germanio, estano, cobre, arsenico y antimonio. Ademas, compararon los productos radiactivos de retroceso formados como consecuencia de los procesos de captura K en {sup 68}Ge-tetrafenilo con los resultados obtenidos mediante el proceso (n, {gamma}) en Ga-trifenilo y el proceso (n,p) en Ge-tetrafenilo. Por ultimo, estudiaron tambien la transicion {beta

  1. Épidémiologie de l'intoxication par envenimation chez les enfants ...

    African Journals Online (AJOL)

    Introduction: L'intoxication par envenimation est l'ensemble des manifestations locales et générales induites par la pénétration dans l'organisme d'une substance toxique produite par un animal venimeux. Le but de notre travail était d'étudier les signes cliniques des intoxications par envenimation chez les enfants de 0 à 15 ...

  2. Contribution to the analysis of light elements using x fluorescence excited by radio-elements; Contribution a l'analyse des elements legers par fluorescence x excitee au moyen de radioelements

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    In order to study the possibilities of using radioactive sources for the X-fluorescence analysis of light elements, the principle is given, after a brief description of X-fluorescence, of the excitation of this phenomenon by X, {beta} and {alpha} emission from radio-elements. The operation and use of the proportional gas counter for X-ray detection is described. A device has been studied for analysing the elements of the 2. and 3. periods of the Mendeleev table. It makes it possible to excite the fluorescence with a radioactive source emitting X-rays or a particles; the X-ray fluorescence penetrates into a window-less proportional counter, this being made possible by the use of an auxiliary electric field in the neighbourhood of the sample. The gas detection pressure leading to the maximum detection yield is given. The spectra are given for the K{sub {alpha}} lines of 3. period elements excited by {sup 55}Fe, {sup 3}H/Zr and {sup 210}Po sources; for the 2. period the K{sub {alpha}} spectra of carbon and of fluorine excited by the {alpha} particles of {sup 210}Po. (author) [French] Afin d'etudier les possibilites d'emploi de sources radioactives a l'analyse par fluorescence X des elements legers, on presente apres rappel de notions generales sur la fluorescence X, le principe de l'excitation de ce phenomene par emission X, {beta}, {alpha} de radioelements. Le fonctionnement et l'utilisation du compteur proportionnel a gaz a la detection du rayonnement X est developpe. Un dispositif permettant l'analyse des elements des 2eme et 3eme periodes de la classification de Mendeleev est etudie. Il permet l'excitation de la fluorescence par source radioactive emettrice de rayons X ou de particules {alpha}; le rayonnement X de fluorescence penetre dans un compteur proportionnel depourvu de fenetre, ceci est rendu possible en creant un champ electrique auxiliaire au voisinage de l'echantillon. On definit une pression du gaz de detection pour un rendement de detection maximal

  3. Contribution to the analysis of light elements using x fluorescence excited by radio-elements; Contribution a l'analyse des elements legers par fluorescence x excitee au moyen de radioelements

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    In order to study the possibilities of using radioactive sources for the X-fluorescence analysis of light elements, the principle is given, after a brief description of X-fluorescence, of the excitation of this phenomenon by X, {beta} and {alpha} emission from radio-elements. The operation and use of the proportional gas counter for X-ray detection is described. A device has been studied for analysing the elements of the 2. and 3. periods of the Mendeleev table. It makes it possible to excite the fluorescence with a radioactive source emitting X-rays or a particles; the X-ray fluorescence penetrates into a window-less proportional counter, this being made possible by the use of an auxiliary electric field in the neighbourhood of the sample. The gas detection pressure leading to the maximum detection yield is given. The spectra are given for the K{sub {alpha}} lines of 3. period elements excited by {sup 55}Fe, {sup 3}H/Zr and {sup 210}Po sources; for the 2. period the K{sub {alpha}} spectra of carbon and of fluorine excited by the {alpha} particles of {sup 210}Po. (author) [French] Afin d'etudier les possibilites d'emploi de sources radioactives a l'analyse par fluorescence X des elements legers, on presente apres rappel de notions generales sur la fluorescence X, le principe de l'excitation de ce phenomene par emission X, {beta}, {alpha} de radioelements. Le fonctionnement et l'utilisation du compteur proportionnel a gaz a la detection du rayonnement X est developpe. Un dispositif permettant l'analyse des elements des 2eme et 3eme periodes de la classification de Mendeleev est etudie. Il permet l'excitation de la fluorescence par source radioactive emettrice de rayons X ou de particules {alpha}; le rayonnement X de fluorescence penetre dans un compteur proportionnel depourvu de fenetre, ceci est rendu possible en creant un champ electrique auxiliaire au voisinage de l'echantillon. On definit une pression du gaz de detection

  4. Evidence of a genetic instability induced by the incorporation of a DNA precursor marked with tritium; Mise en evidence d'une instabilite genetique induite par l'incorporation d'un precurseur de L'ADN marque au tritium

    Energy Technology Data Exchange (ETDEWEB)

    Saintigny, Y.; Laurent, D.; Lahayel, J.B. [CEA Fontenay-aux-Roses, IRCM-LRTS, U967 - CEA/INSERM/Universites Paris 7 and Paris-11, 92 (France); Roche, St.; Meynard, D.; Lopez, B.S. [CEA Fontenay-aux-Roses, LMR - UMR 217 - CEA/CNRS, Institut de Radiobiologie Cellulaire et moleculaire, Direction des Sciences du Vivant, 92 (France)

    2009-07-01

    The authors report a molecular geno-toxicology investigation which allowed molecular events induced par intracellular incorporation of tritium to be studied, and the genetic instability resulting from a chronic exposure even at low dose to be analysed. For this purpose, they developed cell models (hamster tumorous cells and human fibroblasts) in which they know how to incorporate given quantities of marked nucleotides in the DNA. They show that the incorporation of tritium, even with doses which are said to be non toxic, causes a prolonged exposure of the cell to a genotoxic stress, and maybe a genetic instability due to a too great number of recombination events

  5. Automation on computers of the partial area method for the analysis of 's' neutron induced resonances. I. Without interference terms. (1962); Automatisation sur ordinateur de la methode des aires partielle dans l'analyse des resonances induites par les neutrons 's'. I. sans terme d'interference. (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, G; Corge, C R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    This report deals with numerical analysis of transmission resonances induced by 's' wave neutrons in time of flight experiments. The analysis method used is the partial area one. The only case treated here, in this first part, is the one when the interference term can be neglected. Programs and subroutines are thoroughly described, which determine from experimental raw data the resonant transmission, the partial areas, and the resonance parameters. (authors) [French] Le present rapport a pour objet l'analyse numerique sur ordinateur IBM 7090, des resonances dues aux neutrons 's' dans les experiences de transmission par temps de vol, la methode d'analyse utilisee etant la methode des aires partielles. Dans cette premiere partie, seul a ete envisage le cas ou le terme d'interference peut etre neglige. On y trouvera une description detaillee des programmes et sous programmes elabores pour determiner les transmissions resonantes avec leur trace, a partir des donnees experimentales brutes, les aires partielles afferentes ainsi que les parametres caracteristiques des resonances. (auteurs)

  6. Copolymerization of Ethylene Induced by Cobalt-60 Gamma Radiation; Copolymerisation de l'ethylene induite par des rayons gamma du cobalt-60; Sopolimerizatsiya ehtilena pod dejstviem gamma-izlucheniya ot istochnika ks'yali-60; Copolimerizacion del etileno inducida por las radiaciones gamma del cobalto-60

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, M.; Colombo, P. [Brookhaven National Laboratory, Long Island, NY (United States)

    1963-11-15

    }C et a des pressions initiales allant jusqu'a 680 atm. On a procede aux experiences, en milieu statique, dans des systemes a deux phases, a l'exception du systeme ethylene-oxyde de carbone. La separation des copolymeres a ete obtenue par des methodes d'extraction par solvant et de precipitation fractionnee. L'identification a ete faite au moyen de la spectroscopic aux infrarouges. La composition a ete determinee par analyse elementaire. Les auteurs donnent une evaluation partielle de certains produits de la reaction, y compris les points de fusion cristalline, les densites, les caracteristiques de solubilite et les poids moleculaires. La copolymerisation de l'ethylene a ete etablie avec chacun des monomeres suivants : styrene, methacrylate de methyle, acetate de vinyle, acrylonitrile, acetate d'allyle, isobutylene, chlorotiifluoroethylene, transbutene-2, acrylate de methyle, isoprene, propylene, chlorure de vinyle, butene-1, cis-butene-2, oxyde de carbone, pyrrolidone de vinyle, methyle- vinyle-cetone et divinyle-benzene. Les auteurs ont trouve que les donnees experimentales obtenues dans l'etude du systeme ethylene-oxyde de carbone suivaient une forme lineaire de l'equation de composition du copolymere. Pour le rapport {alpha} des constantes de vitesse specifiques de l'oxyde de carbone et de l'ethylene, ils ont determine la valeur 22,0, ce qui montre que l'oxyde de carbone en tant que monomere est active a tel point qu'il se fixe a l'extremite d'une chaftie de radicaux libres d'ethylene 22 fois plus vite que ne le fait un monomere d'ethylene. (author) [Spanish] Los autores estudiaron la copolimerizacion del etileno, inducida por las radiaciones gamma, con una serie de diversos monometos, a 20{sup o}C y presiones iniciales de hasta 680 atm. Los experimentos se llevaron a cabo estaticamente en sistemas bifasicos, salvo en el caso del etileno-oxido de carbono. La separacion de los copolimeros se llevo a cabo por extraccion mediante disolventes y por precipitacion

  7. Investigation of double strand breaks induced by alpha particle irradiation using C.N.B.G. microbeam in human keratinocytes; Mise en evidence de cassures double brin de l'ADN induites par irradiation de keratinocytes humains en microfaisceau alpha

    Energy Technology Data Exchange (ETDEWEB)

    Pouthier, Th

    2006-12-15

    To understand the mechanisms of interaction of ionizing radiation with living tissues exposed to low and protracted doses remains a major issue for risk evaluation. The response cannot be found in epidemiological studies because the only available data concern accidental exposures to high doses of radiation. The natural exposure represents the main source of exposure in the daily life, just before the medical sources (radiology, radiotherapy). In addition, this kind of exposure is very difficult to reproduce in vitro by irradiating cell lines. The method per preference is based on random irradiation of cell populations. The mean number of particles having traversed cells is then calculated on the basis of Poisson statistics. In addition to inevitable multiple impacts, the numerous potential intracellular targets (nuclei, cytoplasm), the indirect effects induced by the impact of particles on neighbouring cells or simply the extracellular targets, constitute phenomena that make more complex the interpretation of experimental data. A charged particle microbeam was developed at C.E.N.B.G. to perform the targeted irradiation of individual cells with a targeting precision of a few microns. It is possible to deliver a counted number of alpha particles down to the ultimate dose of one alpha per cell, to target predetermined cells and then to observe the response of the neighbouring cells. This facility has been validated during this work on human keratinocyte cells expressing a recombinant nuclear fluorescent protein (histone H2B-GFP). The combination of ion micro-beams with confocal microscopy and numeric quantitative analysis allowed the measurement of DNA double strand breaks via the phosphorylation of the histone H2A.X in individual cells. The mechanisms of DNA reparation and apoptosis induction were also in the scope of those studies. The experimental results obtained during this thesis validate the methodology we have developed by demonstrating the targeting

  8. Folie induite: relato de um caso à margem das classificações atuais

    OpenAIRE

    Cunha,Fernando Toledo da; Ladeira,Rodolfo Braga; Salgado,João Vinícius; Nicolato,Rodrigo

    2008-01-01

    Na classificação de Gralnick, de 1942, a folie à deux é dividida em quatro subtipos básicos: folie imposée, folie communiquée, folie simultannée e folie induite. O último termo se refere à adição de novas idéias delirantes por paciente previamente psicótico sob influência de outro paciente. Relatamos um caso de folie induite ocorrido entre mãe e filho primariamente psicóticos (transtorno delirante e esquizofrenia, respectivamente), que passaram a compartilhar delírios de natureza persecutória...

  9. Risks induced by laser radiation; Risques induits par le rayonnement laser

    Energy Technology Data Exchange (ETDEWEB)

    Courant, D [CEA Fontenay-aux-Roses, 92 (France). Dept. de Radiobiologie et de Radiopathologie

    2001-07-01

    The use of lasers is often dangerous because of the emitted power, the wave length, the conduction system(optical fiber, wave guide, mirrors) and the use conditions. The safety notion involves the precise knowledge of materials, the biological effects in function of laser emission parameters, the knowledge of protection standards, the observance of use rules and the personnel training. This chapter treats the risks induced by the beam. It gives the different biological effects induced by the laser beam, at the eye and skin levels that are at the origin of exposure limits and the lasers classification recommended by the protection standards. (N.C.)

  10. Amplification macroscopique de mouvements nanométriques induits par des machines moléculaires

    OpenAIRE

    Goujon , Antoine

    2016-01-01

    The last twenty years have seen tremendous progresses in the design and synthesis of complex molecular machines, often inspired by the beauty of the machinery found in biological systems. However, amplification of the molecular machines motion over several orders of magnitude above their typical length scale is still an ambitious challenge. This work describes how self-organization of molecular machines or motors allows for the synthesis of materials translating the motions of their component...

  11. Approche numérique de la plasticité induite par transformation ...

    African Journals Online (AJOL)

    Key words: Transformation induced plasticity; micromechanical modelling; diffusive transformation; ... Un essai typique de Taleb et al [19] a .... résultant de la simulation éléments finis, ..... Processes Modelling and Computer ... Transformations in Ferrous Alloys : Some. Discrepancies Between Experiments and. Modeling,.

  12. Effets plasmoniques induits par des nanostructures d’argent sur des couches minces de silicium

    OpenAIRE

    MAILHES , Romain

    2016-01-01

    Thin-film photovoltaics focus on lowering the cost reduction of photovoltaic energy through the significant reduction of raw materials used. In the case of thin-films crystalline silicon, the reduction of the thickness of the cell is linked to a drastic decrease of the absorption, particularly for the higher wavelengths. This decrease of the absorption can be fought through the use of several different light trapping methods, and the use of plasmonic effects induced by metallic nanostructures...

  13. Approche numérique de la plasticité induite par transformation ...

    African Journals Online (AJOL)

    The mechanical phenomenon called TRIP (Transformation Induced Plasticity), corresponding to a permanent strain induced by a phase .... produite (phase α). 2.1.1 Décomposition de la déformation. Le tenseur de déformation totale E tot. , résultant de la simulation éléments finis, est décomposée comme suit : E tot. = E el. +.

  14. A study of the fluorescence of the rare gases excited by nuclear particles. Use of the principle for the detection of nuclear radiation by scintillation; Etude de la fluorescence des gaz rares excites par des particules nucleaires. Utilisation pour la detection des rayonnements nucleaires par scintillation

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-12-15

    In the first part is studied the properties of atoms excited by the passage of {alpha} particles through the various rare gases at atmospheric pressure. A spectral analysis of the emitted light showed that certain impurities play an important part in producing the fluorescence, and it has led to the conclusion that the light emission contains at least two components - one very short - lived due to the direct deexcitation of the rare gas, the other relatively slower due to the energy transfers to the impurity. The measurement of the life-time of the excited states has confirmed this foregoing hypothesis, the rapid part of the impulse is extremely short: less than 2,25.10{sup -9} s in the case of xenon; the slower part has a life-time depending directly on the nitrogen concentration, nitrogen being the impurity giving the largest effect in all cases. The study of rare gases under the influence of an electric field has made it possible to show that the amount of light produced by an {alpha} particle can be multiplied (by 60, for example, in a field of 600 V:cm) so that the luminescent efficiency is greater than in the case of INaTI. In the second part the characteristics of the rare gases acting as scintillators is examined, the most important property being the absence of fluorescence saturation when the intensity of the excitation incident on the gas is very large. This, together with the very short time of scintillation has made it possible to study a certain number of nuclear physical applications (heavy particle energy-measurements, kinetic studies on nuclear reactors, neutron spectroscopy). (author) [French] On etudie dans la premiere partie les proprietes des atomes excites par le passage de particules {alpha} dans les differents gaz rares a la pression atmospherique. L'etude spectrale de la lumiere emise a montre que certaines impuretes jouent un role considerable dans la fluorescence et on a ete amene a penser que l'emission de lumiere comporte au moins deux

  15. Folie induite: relato de um caso à margem das classificações atuais Folie induite: report of a case outside of the actual classifications

    Directory of Open Access Journals (Sweden)

    Fernando Toledo da Cunha

    2008-01-01

    Full Text Available Na classificação de Gralnick, de 1942, a folie à deux é dividida em quatro subtipos básicos: folie imposée, folie communiquée, folie simultannée e folie induite. O último termo se refere à adição de novas idéias delirantes por paciente previamente psicótico sob influência de outro paciente. Relatamos um caso de folie induite ocorrido entre mãe e filho primariamente psicóticos (transtorno delirante e esquizofrenia, respectivamente, que passaram a compartilhar delírios de natureza persecutória e sexual. Casos de folie à deux geralmente correspondem ao transtorno psicótico induzido (DSM-IV-TR ou transtorno delirante induzido (CID-10. No entanto, o paciente deste relato não pode receber tais diagnósticos, já que nos critérios validados atualmente percebe-se a exigência de que o parceiro induzido não possua um transtorno psicótico anterior ao início do compartilhamento do delírio. Consideramos que o presente relato exemplifica a insuficiência das modernas classificações nesta área. Casos de folie induite podem necessitar de manejo distinto dos demais casos de psicose compartilhada ou não compartilhada. Sugerimos que os critérios diagnósticos correntes poderiam ser revisados para incluir condições psiquiátricas como essa.In the Gralnick classification of 1942 the term folie à deux is classically divided into four basic subtypes: folie imposée, folie communiquée, folie simultannée and folie induite. This last one refers to the addiction of new delusions in a previous psychotic patient, under the influence of another patient. We report a case of folie induite that occurred between mother and son, both diagnosed previously with psychotic disorders (delusional disorder and schizophrenia, respectively, who started to share persecutory and sexual delusions. Cases of folie à deux generally correspond to the induced psychotic disorder in the DSM-IV-TR or the induced delusional disorder in the ICD-10. However, our

  16. Heavy element concentration determination by the x-ray fluorescence analysis using radioisotope {gamma}-ray sources; Dosage d'elements lourds par fluorescence X utilisant des radio-sources de rayons gamma

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, S [Commissariat a l' Energie Atomique, Dir. des Materiaux et des Combustibles Nucleaires, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    A theoretical and experimental study has been made on the fluorescence analysis of high atomic number element, using {gamma}-ray sources for excitation and characteristic K X-rays for the measurement. The choice of the proper {gamma}-ray energy according to the conditions of the determination is considered. The author has studied the usefulness of using the backscattered {gamma}-rays as a correction mean for matrix and grain-size effects. Sources of {sup 153}Gd, {sup 57}Co, {sup 137}Cs have been used for excitation using collimated geometries. Concentration measurements of tungsten in steel, tungsten and lead in aqueous solution, PbS in SiO{sub 2}-PbS powder mixtures have been done, as well as thickness evaluation of gold layers on copper. A precision of about 0.2 per cent (abs.) is obtained for lead determination in light matrixes. A probe design is proposed for the continuous determination of lead in aqueous solutions. (author) [French] On etudie de maniere theorique et experimentale l'analyse d'elements a nombre atomique eleve par fluorescence en utilisant des sources de rayons {gamma} pour l'excitation, et des rayons-X K caracteristiques pour la mesure. On considere le choix de l'energie appropriee des rayons {gamma} suivant les conditions experimentales. L'utilite d'employer les rayons {gamma} retrodiffuses pour corriger les effets de la matrice et de la dimension des grains est etudiee. Des sources de {sup 153}Gd, de {sup 57}Co et de {sup 137}Cs a geometrie collimatee ont ete utilisees pour l'excitation. Des mesures de la concentration du tungstene dans l'acier, du tungstene et du plomb en solutions aqueuses, et du PbS dans des melanges de poudre SiO{sub 2}-PbS ont ete entreprises ainsi que l'evaluation de l'epaisseur des couches d'or sur le cuivre. On obtient une precision d'environ 0,2 pour cent (en absolu) pour la determination du plomb dans des matrices legeres. On propose un modele de sonde pour la determination en continu du plomb en solution aqueuse

  17. Effet thérapeutique de l’extrait aqueux de Globularia alypum suite à une insulinotoxicité induite in vitro sur les cardiomyocytes de Rattus norvegicus. [Therapeutic effect of aqueous extract of Globularia alypum following in vitro insulin induced toxicity on Rattus norvegicus cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Leila SMAIL

    2017-07-01

    Full Text Available Introduction. L’insulino‐résistance, marquée par une réaction inflammatoire via la production de TNF‐α et par l’hyperinsulinémie compensatoire, conduit à long terme à l’installation d’une glucolipotoxicité et du diabète de type 2. Objectif. Dans cette étude, les effets d’un extrait aqueux de Globularia alypum (Ga a été analysé in vitro, suite à un stress induit sur le cardiomyocyte de Rattus norvegicus. Matériel et Méthodes. Le stress a été induit par addition d’une dose élevée d’insuline (10 UI/ mL. Les taux de prolifération ont été déterminés par comptage et les contenus cellulaires en monoxyde d’azote (NO, en malondialdéhyde (MDA et en catalase ont été évalués. Résultats. En présence de la dose élevée d’insuline, les cardiomyocytes ont montré une diminution de la survie cellulaire, un déséquilibre du statut redox en faveur d’une augmentation de NO et de MDA et d’une diminution d’une enzyme du système antioxydant, la catalase. Suite à l’action de l’extrait de Ga, il a été noté une amélioration du taux de prolifération cellulaire, une diminution du taux de No et de MDA ainsi qu’une augmentation de l’activité de la catalase. Conclusion. L’état de stress induit sur le cardiomyocyte par l’insulino‐résistance, mimé par la dose élevée d’insuline, entraîne des altérations physiologiques et biochimiques. Ces dernières, précurseurs de mort cellulaire par apoptose sont atténuées après addition d’un extrait de Globularia alypum, lequel pourrait constituer une cible thérapeutique en aval de l’installation du DT2.

  18. Automation on computer of the partial area method in the analysis of resonances induced by 'S' neutrons 2. with an interference term and extension of the method to the treatment of multi resonances (1963); Automatisation sur ordinateur de la methode des aires partielles dans l'analyse des resonances induites par les neutrons ''S''. 2, avec terme d'interference et extension de la methode au traitement des multiresonances (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, G; Corge, C R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    This report deals with the numerical analysis on an I.B.M. 7090 computer of transmission resonances induced by 's' wave neutrons in time of flight experiments. The analysis method used is the partial area one. In this second part the interference term is taken into account. Modifications have been made in the programs and subroutines described in the first part, to determine the resonant transmissions from experimental raw data, and the relating partial areas. Also programs and subroutines are thoroughly described, which estimate the resonance parameters. The field of the partial area method has been extended to cover the case where several resonances have to be treated simultaneously, provided they do not interfere. (authors) [French] Le pretent rapport a pour objet l'analyse numerique sur ordinateur I.B.M. 7090 des resonances dues aux neutrons ''s'' dans les experiences de transmission par temps de vol, la methode d'analyse utilisee etant la methode dea aires partielles. Dans cette deuxieme partie il a ete tenu compte du terme d'interference. On y trouvera une description des amenagements apportes aux programmes et sous-programmes decrits dans la premiere partie pour determiner les transmissions interfero-resonnantes a partir des donnees experimentales brutes et les aires partielles afferentes. Sont egalement decrits les programmes et sous-programmes necessaires au calcul des parametres caracteristiques des resonances. Le domaine d'application de la methode a ete etendu au traitement simultane de plusieurs resonances groupees n'interferant pas entre elles. (auteurs)

  19. L'Empowerment au coeur des bouleversements induits par les TIC dans la gestion des ressources humaines

    OpenAIRE

    Blavier, André

    2012-01-01

    Observer l’influence des TIC (Technologies de l’Information et de la Communication” sur les ressources humaines à la lumière du seul débat “pour ou contre les réseaux sociaux dans l’entreprise ou l’organisation ?” est une approche bien trop restrictive. Les défis relatifs à l’évolution des ressources humaines s’inscrivent dans une perspective plus large, celle d’un environnement numérique global. Comme l’a souligné le rapport “Digital Economy Rankings 2010” d’IBM en collaboration avec l’Econ...

  20. Collision induced fragmentation dynamics of small metallic clusters; Dynamique de fragmentation induite par collision de petits agregats metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Picard, Y

    1999-04-15

    The goal of this work is the complete analysis of the fragmentation of alkali clusters (Na{sub n}{sup +} (n < 10), NaK{sup +} and K{sub 2}{sup +}) induced by collision with light atomic (He) or molecular (H{sub 2}) targets. The main point is to study how the energy is transmitted to the cluster during the collision and how this energy is shared among the various degrees of freedom of the system and leads to its fragmentation. Two types of interactions govern the collision induced dissociation processes: on one hand, the electronic mechanisms where the target perturbs the electronic cloud and brings the molecule into a dissociative state, and on the other hand, the impulsive mechanisms where the momentum transferred to the atomic cores leads to the rotational-vibrational dissociation of the molecule. The experimental procedure is based on the measurement of the velocity vectors of the outgoing fragments detected in coincidence. This allows to reconstruct the full kinematics of the fragmentation and to separate and characterize for the first time the two types of interactions. The two basic mechanisms of collision induced dissociation are then clearly resolved for the diatomic molecule Na{sub 2}{sup +}. For the heteronuclear molecular ion NaK{sup +}, it is shown that the dissociation process is due to a combination of electronic and impulsive mechanisms in some of the dissociation pathways. The extension to the study of metallic clusters Na{sub n}{sup +} (n < 10) fragmentation shows the role and the relative importance of the electronic and impulsive mechanisms and their evolution with the cluster size. The complete analysis of Na{sub 3}{sup +} multi-fragmentation is also presented. (author)

  1. Rupture intergranulaire induite par l'hydrogène dans les alliages d'aluminium-magnésium

    OpenAIRE

    Pouillier , Édouard

    2011-01-01

    Aluminium alloys that are strengthened by alloying elements in solid solution may present a particular sensitivity to intergranular stress corrosion cracking as a result of intergranular dissolution. In Al-5Mg alloys such as AA5083, precipitation of the β-phase (Al3Mg2) at grain boundaries strongly favours intergranular fracture. Previous experimental studies revealed that local plasticity seems to play a significant role in crack initiation. Nevertheless, the exact role of crystal plasticity...

  2. Some results on the fluorescence of gases excited by high-energy charged particles; Quelques resultats concernant la fluorescence de gaz excites par des particules chargees de grande energie

    Energy Technology Data Exchange (ETDEWEB)

    Koch, L; Lesureur, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The essential characteristics of rare gases for use as scintillators are as follows: a very brief period of luminescence, generally less than 10{sup -8} s; a linear response as a function of the energy lost by the nuclear particle in the gas, even in the case of strongly ionising particles (fission fragments). In the gaseous or condensed state therefore, they are of great interest in nuclear physics. (author) [French] Les caracteristiques essentielles des gaz rares en tant que scintillateurs sont: une duree de luminescence tres breve, inferieure a 10{sup -8} s en general; une reponse lineaire en fonction de l'energie perdue par la particule nucleaire dans le gaz, meme dans le cas de particules fortement ionisantes (fragments de fission). A l'etat gazeux ou condense, ils presentent donc un grand interet en physique nucleaire. (auteur)

  3. New developments in the analysis and measurement of thicknesses by excitation of the fluorescent lines by means of {beta} particles; Nouveaux developpements de l'analyse et de la mesure des epaisseurs par excitation des raies de fluorescence au moyen de particules {beta}

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Seibel, G [Institut de Recherches de la Siderurgie, 78 - Saint-Germain-en-Laye (France)

    1960-07-01

    The process for analysing and measuring the thickness of deposits by {beta}-X fluorescence which we have already described has undergone further development. The use of promethium-147 and krypton-85 sources makes it possible to reduce the background noise which is observed with strontium-90. We present the results obtained for various measurements of the thickness of metallic coatings and the continuous measurement of calcium and of iron in ore samples. We describe the tests carried out with a view to analysing the X-rays by means of a crystal. (author) [French] Le procede d'analyse et de mesure des epaisseurs de depots par fluorescence {beta}-X que nous avons precedemment decrit a fait l'objet de nouveaux developpements. L'emploi de sources de prometheum-147 et de krypton-85 permet de reduire le bruit de fond que l'on observe avec le strontium-90. Nous dormons les resultats obtenus pour diverses mesures d'epaisseurs de depots metalliques et la mesure en continu du calcium et du fer dans les carottes de minerais. Nous decrivons les essais effectues en vue d'analyser le rayonnement X au moyen d'un cristal. (auteur)

  4. The in vitro synthesis of {beta}-galactosidase induced in a subcellular structure of Escherichia coli (1961); Synthese in vitro de {beta}-galactosidase induite dans une structure subcellulaire d'Escherichia coli (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Nisman, B; Kayser, A; Demailly, J; Genin, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    Isopropyl-thio-galactoside (IPTG), an inducer of 3-galactosidase, makes it possible to synthesise this enzyme in vitro with the subcellular structure (P{sub 1}). The enzyme is isolated from the bacteria Escherichia coli K 12 which are inductive but not induced. The incorporation of radioactive amino-acids, which is stimulated by the presence of an inducer, was studied during the course of the enzyme synthesis. Saccharose suppresses the induction of {beta}-galactosidase. The presence of a specific inhibitor in the structure studied is considered. (authors) [French] L'isopropylthiogalactoside (IPTG), inducteur de la 3-galactosidase, permet la synthese in vitro de cette enzyme dans la structure subcellulaire (P{sub 1}) isolee a partir des bacteries d'Escherichia coli K 12, inductibles mais non induites. L'incorporation d'acides amines radioactifs, stimulee par la presence d'inducteur, a ete etudiee au cours de la synthese de l'enzyme. Le saccharose supprime l'induction de la 3-galactosidase. La presence du represseur specifique dans la structure etudiee est consideree. (auteurs)

  5. Assessment of in vivo fluorescence method for chlorophyll-a estimation in optically complex waters (Curuai floodplain, Pará - Brazil Avaliação do método de fluorescência in vivo para a estimativa da concentração de clorofila-a em águas opticamente complexas (planície de inundação do Curuai, Pará - Brasil

    Directory of Open Access Journals (Sweden)

    Rafael Damiati Ferreira

    2012-12-01

    method, it is very useful for assessing the chlorophyll spatial distribution with relatively low cost. These possibilities are very interesting in the execution of field missions in the Amazon region.OBJETIVO: Este trabalho descreve os experimentos realizados para avaliar as medidas de fluorescência in vivo (IVF em um ambiente aquático opticamente complexo (planície de inundação amazônica, como método alternativo para a quantificação da clorofila-a na água. MÉTODOS: Foram coletados parâmetros de qualidade da água em 26 estações amostrais distribuídas em diversos lagos da planície de inundação de Curuai: temperatura, pH, turbidez, condutividade, profundidade, transparência ao disco de Secchi, concentração de clorofila-a (Chl-a, total de sólidos em suspensão (TSS e carbono orgânico dissolvido (DOC simultaneamente a quilômetros de transectos de IVF. Dois métodos de determinação do valor de fluorescência foram testados para o ajuste de modelos de estimativa da concentração de clorofila: fluorescência instantânea e fluorescência média. Também foram testados um modelo global e modelos regionais, os quais foram analisados em termos dos componentes opticamente ativos na água (Chl-a, DOC e TSS. RESULTADOS: Os resultados indicam que independentemente do método de estimativa de fluorescência empregado, não foi possível ajustar um modelo global para a planície de Curuai. Os modelos regionais apresentaram resultados contrastantes, de acordo com a concentração dos componentes opticamente ativos. Melhores resultados foram observados nos sistemas aquáticos com um único componente dominante, distribuído homogeneamente pelo respectivo lago. Os resultados destacam a influência das razões Chl-a/TSS, Chl-a/DOC e Feofitina/Chl-a no ajuste entre a IVF e a Chl-a. CONCLUSÕES: Não foi possível ajustar um modelo global para a planície de Curuai através de medidas de IVF. Entretanto, a busca por modelos regionais forneceu informações sobre os

  6. Fast neutron dosimetry and spectrometry using radioactivation (1963); Dosimetrie et spectrometrie des neutrons rapides par radioactivation (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    The author first recalls rapidly a few generalities concerning induced radioactivity detectors and gives, in an appendix, tables summarizing the properties of detector elements which may be used in radioprotection. The excitation functions found in the literature and also given. The technological characteristics of the detectors used are given, together with the counting methods. The many advantages of activation dosimetry for strong or periodic neutron fluxes and for those in the presence of {gamma}-radiation are stressed. The main problem in activation dosimetry is, however, the calculation of the dose absorbed from the results of the measurements. It is shown how the dose is expressed, fairly accurately, as a function of the radioactivities induced in a series of detectors. As an example, the spectrometry and the dosimetry of the neutron flux emitted by a Po-Be source are presented. (author) [French] L'auteur fait d'abord un bref rappel des generalites sur les detecteurs a radioactivite induite, accompagne, en annexe, des tableaux resumant les proprietes d'elements detecteurs utilisables en radioprotection. Les fonctions d'excitation trouvees dans la litterature y sont egalement annexees. On donne ensuite les caracteristiques technologiques des detecteurs employes ainsi que les methodes de comptage utilisees. On souligne les nombreux avantages de la dosimetrie par activation dans les flux de neutrons intenses ou periodiques et en presence de rayonnement {gamma}. Il reste que le probleme central de la dosimetrie par activation est le calcul de la dose absorbee a partir des resultats de mesure. On montre comment la dose s'exprime, de maniere approchee, en fonction des radioactivites induites dans une serie de detecteurs. A titre d'exemple, la spectrometrie et la dosimetrie du flux de neutrons emis par une source de Po-Be sont presentees. (auteur)

  7. Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

    Science.gov (United States)

    Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

    2015-01-01

    Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

  8. Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

    Directory of Open Access Journals (Sweden)

    Grégory Baronian

    Full Text Available Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

  9. Caractérisation de l'état chimique d'un élément par fluorescence X : l'aluminium dans les zéolithes Characterizing the Chemical State of an Element by X-Ray Fluorescence: Aluminium in Zeolites

    Directory of Open Access Journals (Sweden)

    Freund E.

    2006-11-01

    Full Text Available La fluorescence X est essentiellement connue dans le domaine de l'analyse quantitative, mais c'est aussi une méthode qui permet d'obtenir des informations détaillées sur la structure électronique des éléments. Dans cet article, nous montrons qu'il est possible de mettre au point une technique simple de caractérisation de l'état chimique d'un élément en utilisant de façon conjointe un spectromètre commercial et un programme adapté de traitement des données. Nous avons appliqué cette technique au cas de l'aluminium dans une zéolithe particulière : la mordénite dite à petits pores modifiée par différents traitements. Nous avons ainsi pu classer les solides suivant leur rapport (AI hexa-coordinné/AI tétracoordinné et montrer que le débouchage de la mordénite dite à petits pores est lié à l'extraction d'atomes d'aluminium de la charpente cristalline. X-ray fluorescence is mainly known in the field of qua-titative analysis, but it is also a useful method for obtaining detailed informations about the electronic structure of elements. This article shows that it is possible to develop a simple technique for characterizing the chemical state of an element by combining a commercial spectrometer with a program suited for data processing. This technique has been applied to the case of aluminum in a specific zeolite, ( small portmodernite, modified by various treatments. We were thus able to classify the solids according to the ratio of hexacoordinated AI/tetracoordinated AI and to show that the deblocking of the small portmordenite is linked to the extraction of aluminum atomrs from the crystalline structure.

  10. Les activités de gestion d’alerte épidémiologique : les transformations induites par l’utilisation d’un système de surveillance en temps réel Alert Management Activity: Cognitive and team activity modifications due to the use of an early warning system Las actividades de gestión de alerta epidemiológica : las transformaciones inducidas por la utilización de un sistema de vigilancia en tiempo real

    Directory of Open Access Journals (Sweden)

    Charlotte Gaudin

    2012-05-01

    Full Text Available Cet article présente une recherche en psychologie cognitive et ergonomique visant à analyser l’activité de gestion d’une alerte épidémiologique. Gérer une alerte épidémiologique est une activité médicale distribuée et complexe consistant en la gestion d’un environnement dynamique puisque l’épidémie évolue et se propage rapidement si aucune action n’est entreprise pour la contrôler. Plus précisément, deux types de situation sont analysées : (1 l’activité traditionnelle de gestion d’alerte et (2 cette même activité lorsqu’elle est assistée par un système informatique, en l’occurrence le système ASTER (ou Alerte et Surveillance en TEmps Réel. Les résultats obtenus sont ensuite discutés au niveau cognitif et au niveau des activités collectives consécutivement à l’introduction et à l’utilisation d’un système technique.This paper presents a study that investigated the management of epidemiological alerts. Alert management is a complex, distributed medical activity. It can be compared to the largest category of dynamic environment management. Two activities were examined. First, we analyzed traditional alert management activity with the MAD method (observations and interviews. Second, we analyzed and characterized alert management activities when supported by the computerized ASTER system (Alerte et Surveillance en TEmps Réel, alert and monitoring in real time. The second analysis was conducted with EORCA method, which is used to describe collective and complex activities. The results highlight various modifications to both the cognitive activity and team activities which were due to the use of the ASTER system.Este artículo presenta una investigación en psicología cognitiva y ergonómica cuyo objetivo es analizar la actividad de gestión de una alerta epidemiológica. Manejar una alerta epidemiológica es una actividad médica distribuida y compleja que consiste en la gestión de un ambiente

  11. suPAR

    DEFF Research Database (Denmark)

    Hodges, Gethin W; Bang, Casper N; Wachtell, Kristian

    2015-01-01

    The fundamental role of inflammation in cardiovascular disease (CVD) has prompted interest in numerous biomarkers that detect subclinical levels of inflammation. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker that correlates significantly with cardiovascular events ...... comprehensive review of suPAR in CVD and explore its function and usefulness in predicting cardiovascular events....

  12. Rapid evaluation of the neutron dose following a criticality accident by measurement of {sup 24}Na activity; Evaluation rapide de la dose de neutrons a la suite d'un accident de criticite par mesure de l'activite de {sup 24}Na

    Energy Technology Data Exchange (ETDEWEB)

    Estournel, R [Centre de Production de Plutonium de Marcoule, Service de Protection contre les Rayonnements, 30 (France); Henry, Ph [Centre de Production de Plutonium de Marcoule, Section Medicale et Sociale, 30 (France); Beau, P; Ergas, A [Commissariat a l' Energie Atomique, Service d' Hygiene Atomique, Dept. de la Protection Sanitaire, Chusclan, (France)

    1966-07-01

    By external measurement of the gamma activity of {sup 24}Na induced in the human organs by a neutron flux during a criticality accident, it is possible to evaluate the personal dose received. Detectors designed for everyday use in health physics can be applied to these measurements, and this is described in the first part of the work. The response of a certain number of induced-activity detectors is presented. The induced activity-dose relationship is studied theoretically in the second part taking into account the neutron spectrum to which the individual has been subjected. The characteristic spectra of three possible types of accident have been used for deducing this relationship. The results obtained show that the method is sufficiently sensitive for present purposes. The accuracy of this method for calculating the dose received during an experiment is discussed. (authors) [French] La mesure par detection externe de l'activite gamma du sodium 24 induit dans l'organisme humain par un flux de neutrons lors d'un accident de criticite rend possible l'evaluation de la dose recue par un individu irradie. L'utilisation de detecteurs d'un emploi courant en radioprotection fait l'objet d'une experimentation qui constitue la premiere partie de cette etude. La reponse d'un certain nombre de detecteurs a une activite induite connue est presentee. La relation dose-activite induite, est etudiee, de maniere theorique, dans la seconde partie, correlativement au spectre des neutrons qui ont atteint l'individu irradie. Les spectres caracteristiques de trois types d'accidents possibles ont ete retenus pour l'etablissement de ces relations. Les resultats obtenus montrent que la methode satisfait avec une sensibilite suffisante au but recherche. La precision avec laquelle on peut ainsi calculer la dose recue au cours d'un accident de criticite est discutee. (auteurs)

  13. Par Pond water balance

    International Nuclear Information System (INIS)

    Hiergesell, R.A.; Dixon, K.L.

    1996-06-01

    A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

  14. FooPar

    DEFF Research Database (Denmark)

    Hargreaves, F. P.; Merkle, D.

    2013-01-01

    We present FooPar, an extension for highly efficient Parallel Computing in the multi-paradigm programming language Scala. Scala offers concise and clean syntax and integrates functional programming features. Our framework FooPar combines these features with parallel computing techniques. Foo......, results based on a empirical analysis on two supercomputers are given. We achieve close-to-optimal performance wrt. theoretical peak performance. Based on this result we conclude that FooPar allows programmers to fully access Scalas design features without suffering from performance drops when compared...

  15. Activation analysis using {gamma} photons; Analyse par activation aux photons {gamma}

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-07-01

    This report summarizes all the data required for using photonuclear reactions in the field of analysis. After a brief review of the elementary properties of nuclear reactions induced by photon irradiation, the main characteristics are given of high energy (E > 20 MeV) Bremsstrahlung sources. The principle of activation analysis based on the use of photons is given. Actual examples of the analytic possibilities are described in detail, in particular in the case of the determination of very small quantities (< 10{sup -6}) of C, N, O and F. The influence of interfering nuclear reactions is discussed. (author) [French] Ce rapport se propose de resumer l'ensemble des connaissances indispensables pour l'utilisation des reactions photonucleaires a des fins analytiques. Apres quelques rappels concernant les proprietes elementaires des reactions nucleaires induites par irradiation dans les photons, les principales caracteristiques des sources de rayonnement de freinage de haute energie (E > 20 MeV)| sont donnees. Le principe de l'analyse par activation aux photons est rappele. Des exemples concrets sur les possibilites analytiques sont developpes, particulierement en ce qui concerne la determination de quantites tres faibles (< 10{sup -6}) de C, N, O et F. L'influence des reactions nucleaires parasites est discutee. (auteur)

  16. Effet protecteur des feuilles de Opilia celtidifolia contre l'ulcère induit ...

    African Journals Online (AJOL)

    Le Sucralfate a été utilisé comme témoin positif à la dose de 1000 mg/kg et le groupe non traité a reçu de l'eau distillée à10 ml/kg. Les extraits ont été administrés par voie intragastrique, une heure après, 0,5 ml d'éthanol à 90% a été administré aux animaux pour provoquer l'ulcère pendant une heure. Après ce temps, les ...

  17. L'analyse par activation de neutrons de réacteur

    Science.gov (United States)

    Meyer, G.

    2003-02-01

    Quand les neutrons traversent la matière, certains sont transmis sans interaction, les autres interagissent avec le milieu traversé par diffusion et par absorption. Ce phénomène d'absorption est utilisé pour se protéger des neutrons, mais aussi pour les détecter; il peut également être utilisé pour identifier les noyaux “absorbants" et ainsi analyser le milieu traversé. En effet par différentes réactions nucléaires (n,γ), (n,p), (n,α), (n,fission), on obtient des noyaux résiduels qui sont souvent radioactifs; on dit que l'échantillon est “activé". Si l'on connaît le rendement d'activation et donc le pourcentage de noyaux ainsi “transmutés", les mesures de radioactivité induite vont permettre de déterminer la composition de l'échantillon irradié. Cette méthode dite d'analyse par activation neutronique est pratiquée depuis la découverte du neutron. Elle a permis grâce à sa sélectivité et à sa sensibilité d'avoir accès au domaine des traces et des ultra-traces dans des champs d'application très divers comme la métallurgie, l'archéologie, la biologie, la géochimie etc...

  18. A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

    DEFF Research Database (Denmark)

    Gayathri, P; Fujii, T; Møller-Jensen, Jakob

    2012-01-01

    the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture...... of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles....

  19. Le rôle majeur du canal potassique TREK-1 dans la protection neuronale induite par les oméga-3

    Directory of Open Access Journals (Sweden)

    Heurteaux Catherine

    2005-01-01

    Full Text Available The nutritional interest of polyunsaturated fatty acids from omega-3, that are mainly present in vegetal and fish oils is now validated by the scientific community. Their beneficial effects have first been reported in coronary heart diseases. Many neurological and chronic diseases are often related to deficiencies in omega-3 and omega-6 and their derivatives. Polyunsaturated fatty acids from omega-3 family are essential to brain growth and neuronal preserving (foetuses, children, old people as well as visual and cognitive functions. They are recently considered as factors of improvement in some mental diseases. Today, polyunsaturated fatty acids could play a key role in the prevention and/or or the treatment of cerebral diseases. With the development of in vitro and in vivo experimental models, it is now possible to demonstrate the omega-3-induced neuronal protection against major pathologies such as epileptic seizures and cerebral ischemia. The molecular mechanism of neuronal protection induced by omega-3 is now clarified. The omega-3 target would be a potassium channel, TREK-1, which belongs to the new family of 2-P domain potassium channels (K-2P. The discovery of the physiopathological role of these K-2P channels can represent an important therapeutical challenge not only in cerebrovascular diseases, but also in psychiatry.

  20. Multicharged Ion-induced simple molecule fragmentation dynamics; Dynamique de la fragmentation de molecules simples induite par impact d'ion multicharge

    Energy Technology Data Exchange (ETDEWEB)

    Tarisien, M

    2003-10-01

    The aim of this work is to study the dynamics of swift multicharged ion-induced fragmentation of diatomic (CO) and triatomic (CO{sub 2}) molecules. Performed at the GANIL facility, this study used the Recoil Ion Momentum Spectroscopy technique (RIMS), which consists of a time-of-flight mass spectrometer, coupled with a multi-hit capability position sensitive detector (delay line anode). The high-resolution measurement of the kinetic energy distribution released (KER) during the CO fragmentation points out the limitation of the Coulomb Explosion Model, revealing, for example, the di-cation CO{sub 2}{sup +} electronic state contribution in the case of C{sup +}/O{sup +} fragmentation pathway. Furthermore, the multi-ionization cross section dependence with the orientation of the internuclear axis of CO is compared with a geometrical model calculation. Finally, different behaviours are observed for the dissociation dynamics of a triatomic molecule (CO{sub 2}). While triple ionization leads mainly to a synchronous concerted fragmentation dynamics, a weak fraction of dissociating molecule follows a sequential dynamics involving CO{sub 2}{sup +} metastable states. In the case of double ionization, (CO{sub 2}){sup 2+} di-cation dissociation dynamics is asynchronously concerted and has been interpreted using a simple model involving an asymmetrical vibration of the molecule. (author)

  1. Irradiation induced surface segregation in concentrated alloys: a contribution; Contribution a l`etude de la segregation de surface induite par irradiation dans les alliages concentres

    Energy Technology Data Exchange (ETDEWEB)

    Grandjean, Y.

    1996-12-31

    A new computer modelization of irradiation induced surface segregation is presented together with some experimental determinations in binary and ternary alloys. The model we propose handles the alloy thermodynamics and kinetics at the same level of sophistication. Diffusion is described at the atomistic level and proceeds vis the jumps of point defects (vacancies, dumb-bell interstitials): the various jump frequencies depend on the local composition in a manner consistent with the thermodynamics of the alloy. For application to specific alloys, we have chosen the simplest statistical approximation: pair interactions in the Bragg Williams approximation. For a system which exhibits the thermodynamics and kinetics features of Ni-Cu alloys, the model generates the behaviour parameters (flux and temperature) and of alloy composition. Quantitative agreement with the published experimental results (two compositions, three temperatures) is obtained with a single set of parameters. Modelling austenitic steels used in nuclear industry requires taking into account the contribution of dumbbells to mass transport. The effects of this latter contribution are studied on a model of Ni-Fe. Interstitial trapping on dilute impurities is shown to delay or even suppress the irradiation induced segregation. Such an effect is indeed observed in the experiments we report on Fe{sub 50}Ni{sub 50} and Fe{sub 49}Ni{sub 50}Hf{sub 1} alloys. (author). 190 refs.

  2. Study of structural modifications induced by ion implantation in austenitic stainless steel; Etude des modifications structurales induites par implantation ionique dans les aciers austenitiques

    Energy Technology Data Exchange (ETDEWEB)

    Dudognon, J

    2006-12-15

    Ion implantation in steels, although largely used to improve the properties of use, involves structural modifications of the surface layer, which remain still prone to controversies. Within this context, various elements (N, Ar, Cr, Mo, Ag, Xe and Pb) were implanted (with energies varying from 28 to 280 keV) in a 316LVM austenitic stainless steel. The implanted layer has a thickness limited to 80 nm and a maximum implanted element concentration lower than 10 % at. The analysis of the implanted layer by grazing incidence X ray diffraction highlights deformations of austenite lines, appearance of ferrite and amorphization of the layer. Ferritic phase which appears at the grain boundaries, whatever the implanted element, is formed above a given 'threshold' of energy (produced of fluency by the energy of an ion). The formation of ferrite as well as the amorphization of the implanted layer depends only on energy. In order to understand the deformations of austenite diffraction lines, a simulation model of these lines was elaborated. The model correctly describes the observed deformations (broadening, shift, splitting) with the assumption that the expansion of the austenitic lattice is due to the presence of implanted element and is proportional to the element concentration through a coefficient k'. This coefficient only depends on the element and varies linearly with its radius. (author)

  3. Swift heavy ion irradiation effects in {alpha} poly(vinylidene fluoride); Etude des effets induits par les ions lourds energetiques dans le poly(fluorure de vinylidene)

    Energy Technology Data Exchange (ETDEWEB)

    Le Bouedec, A

    1999-11-29

    The goal of this study is to characteristic and to localised defects created in {alpha} Poly (vinylidene fluoride) after swift heavy ion irradiations. PVDF films are irradiated with several Swift Heavy Ions (SHI), in the electronic stopping power (dE/dx){sub e}, in order to study the influence of irradiation parameters (absorbed dose, ion). These irradiated films are studied by different analysis techniques such as FTIR, ESR (X and Q band) spectroscopies and DSC. The crystalline level of PVDF is about 50% and we follow it destruction and amorphization as the absorbed dose increase by DSC and FTIR studies. The variation of the various FTIR bands allow us to observe the unsaturations induced by SHI radiations. Two sets of defects are observed: those which yield is sensitive to an increase of (dE/dx){sub e} and those that are not. A spatial distribution of the various defects within the talent track is provided and defects that are difficult to create are the closest of the ion path. The different kind of radicals created after irradiations are studied by ESR spectroscopy. Alkyl, peroxy and polyenyl radicals are detected after SHI radiations like after electron or {gamma} irradiations. Their yield of creation is independent of (dE/dx){sub e} and their localised in the crystalline zone or/and at the interfacial zone between crystalline and amorphous one. An other kind of radicals is created only after SHI radiations that are specific of the SHI-polymer interaction. We observe that these radicals are localised on a carbon cluster, in the core of the latent track for low doses and highly sensitive at the (dE/dx){sub e} of the ion. (author)

  4. Study of the mechanisms induced by a ionizing particle on simple structures; Etude des mecanismes de base induits par une particule ionisante sur des structures simples

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, G.; Palau, J.M.; Roche, Ph.; Sagnes, B.; Gasiot, J. [Montpellier-2 Univ., CEM2, 34 (France); Calvet, M.C. [Aerospatiale Espace et Defense, 78 - Les Muraux (France)

    1999-07-01

    Ion induced currents in a diode and a semiconductor bar are compared. A short track, located inside the structure, and a long track passing through it are considered. The involved mechanisms are analysed in order to explain why the observed effects are very similar. (authors)

  5. Characterization and pharmacological modulation of intestinal inflammation induced by ionizing radiation; Caracterisation et modulation pharmacologique de l'inflammation intestinale induite par les rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Gremy, O

    2006-12-15

    The use of radiation therapy to treat abdominal and pelvic malignancies inevitably involves exposure of healthy intestinal tissues which are very radiosensitive. As a result, most patients experience symptoms such as abdominal pain, nausea and diarrhea. Such symptoms are associated with acute damage to intestine mucosa including radio-induced inflammatory processes. With a rat model of colorectal fractionated radiation, we have shown a gradual development of a colonic inflammation during radiation planning, without evident tissue injury. This radio-induced inflammation is characterized not only by the sur expressions of pro-inflammatory cytokines and chemokines, a NF-kB activation, but also by a repression of anti-inflammatory cytokines and the nuclear receptors PPARa and RXRa, both involved in inflammation control. This early inflammation is associated with a discreet neutrophil recruitment and a macrophage accumulation. Macrophages are still abnormally numerous in tissue 27 weeks after the last day of irradiation. Inflammatory process is the most often related to a specific immune profile, either a type Th1 leading to a cellular immune response, or a type Th2 for humoral immunity. According to our studies, a unique abdominal radiation in the rat induces an ileum inflammation and an immune imbalance resulting in a Th2-type profile. Inhibiting this profile is important as its persistence promotes chronic inflammation, predisposition to bacterial infections and fibrosis which is the main delayed side-effect of radiotherapy. The treatment of rats with an immuno-modulator compound, the caffeic acid phenethyl ester (C.A.P.E.), have the potential to both reduce ileal mucosal inflammation and inhibit the radio-induced Th2 status. In order to search new therapeutic molecular target, we has been interested in the PPARg nuclear receptor involved in the maintenance of colon mucosal integrity. In our abdominal irradiation model, we have demonstrated that the prophylactic treatment with a PPARg synthetic ligand, the so-called 5-aminosalicylic acid (5-ASA), protects against the development of the acute mucosal colon inflammation. This pharmacological drug restrains radio-induced expression of pro inflammatory molecular actors such as TNFa, MCP-1 and iNOS, it also limits the repression of nuclear receptors involved in inflammation control such as PPARg, and reduces the radio-induced accumulation of macrophages. These results could give some leads to find therapeutic drug to limit radio-induced early mucosal and consequently, to improve patients' comfort during and after the radiotherapy schedule. (author)

  6. Étude des dommages induits dans l'ADN par irradiation laser X-UV à 21.2 nm

    Science.gov (United States)

    Cassou, K.; Ros, D.; Kazamias, S.; Klisnick, A.; Jamelot, G.; Guilbaud, O.; Rus, B.; Kozlová, M.; Polan, J.; Präg, A. R.; Stupka, M.; Eot-Houllier, G.; Sage, E.; Begusová, M.; Stísová, V.; Du Penhoat, M.-A. H.; Touati, A.; Chétioui, A.

    2005-06-01

    We report the preliminary result of the application of the collisional Ne-like soft x-ray laser as radiation source to induce DNA damage. The goal of this experiment was a test bed study of the damage yields induced by soft x-ray radiation in dried plasmid DNA sample. The saturated Ne-like soft x-ray laser available at the PALS facility, delivering several millijoules in a single 100 ps pulse at 21.2 nm was used to irradiate two different plasmids: pSP189 and pBS. The study is centered on the dose effect leading to single and double strand break in DNA.

  7. Characterization and pharmacological modulation of intestinal inflammation induced by ionizing radiation; Caracterisation et modulation pharmacologique de l'inflammation intestinale induite par les rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Gremy, O

    2006-12-15

    The use of radiation therapy to treat abdominal and pelvic malignancies inevitably involves exposure of healthy intestinal tissues which are very radiosensitive. As a result, most patients experience symptoms such as abdominal pain, nausea and diarrhea. Such symptoms are associated with acute damage to intestine mucosa including radio-induced inflammatory processes. With a rat model of colorectal fractionated radiation, we have shown a gradual development of a colonic inflammation during radiation planning, without evident tissue injury. This radio-induced inflammation is characterized not only by the sur expressions of pro-inflammatory cytokines and chemokines, a NF-kB activation, but also by a repression of anti-inflammatory cytokines and the nuclear receptors PPARa and RXRa, both involved in inflammation control. This early inflammation is associated with a discreet neutrophil recruitment and a macrophage accumulation. Macrophages are still abnormally numerous in tissue 27 weeks after the last day of irradiation. Inflammatory process is the most often related to a specific immune profile, either a type Th1 leading to a cellular immune response, or a type Th2 for humoral immunity. According to our studies, a unique abdominal radiation in the rat induces an ileum inflammation and an immune imbalance resulting in a Th2-type profile. Inhibiting this profile is important as its persistence promotes chronic inflammation, predisposition to bacterial infections and fibrosis which is the main delayed side-effect of radiotherapy. The treatment of rats with an immuno-modulator compound, the caffeic acid phenethyl ester (C.A.P.E.), have the potential to both reduce ileal mucosal inflammation and inhibit the radio-induced Th2 status. In order to search new therapeutic molecular target, we has been interested in the PPARg nuclear receptor involved in the maintenance of colon mucosal integrity. In our abdominal irradiation model, we have demonstrated that the prophylactic treatment with a PPARg synthetic ligand, the so-called 5-aminosalicylic acid (5-ASA), protects against the development of the acute mucosal colon inflammation. This pharmacological drug restrains radio-induced expression of pro inflammatory molecular actors such as TNFa, MCP-1 and iNOS, it also limits the repression of nuclear receptors involved in inflammation control such as PPARg, and reduces the radio-induced accumulation of macrophages. These results could give some leads to find therapeutic drug to limit radio-induced early mucosal and consequently, to improve patients' comfort during and after the radiotherapy schedule. (author)

  8. Channel flow induced by wall injection of fluid and particles; Ecoulement induit par injection parietale de fluide et de particules dans un conduit

    Energy Technology Data Exchange (ETDEWEB)

    Feraille, Th.; Casalis, G. [Aerodynamics and Energetics Modeling Dept., 31 - Toulouse (France)

    2003-12-01

    The Taylor flow is the laminar single phase flow induced by gas injection through porous walls, and is assumed to represent the flow inside solid propellant motors. Such a flow is intrinsically unstable, and the generated instabilities are probably responsible for the thrust oscillations observed in the aforesaid motors. However particles are embedded in the propellants usually used, and are released in the fluid by the lateral walls during the combustion, so that there are two heterogeneous phases in the flow. The purpose of this paper is to study the influence of these particles on stability by comparison with stability results from the single phase studies, in a plane two-dimensional configuration. The particles are supposed to be chemically inert and of a uniform size. In order to carry out a linear stability study for this flow modified by the presence of particles, the mean particle velocity field is first determined, assuming that only the gas exerts forces on the particles. This field is sought in a self similar form, which imposes a limit on the size of the particles. However, the particle mass concentration cannot be obtained in a self similar form, but can only, be described by a partial differential equation. The mean flow characteristics being determined, the spectrum of the discretized linear stability operator shows first that particle addition does not trigger any new 'dangerous' modes compared with the single phase flow case. It also shows that the most amplified mode in the case of the single phase flow remains the most amplified mode in the case of the two phase flow. Moreover, the addition of particles acts continuously upon stability results, behaving linearly with respect to the particle mass concentration when the latter is small. The linear correction to the monophasic mode, as well as the evolution of the modes with weak values of the particle mass concentration at the wall, are shown to be proportional to the ejection velocity of the particles. Then, the evolution of the Eigenmodes from a given injection speed of the particles to another one is deduced by affinity, all other parameters being fixed. With a fixed Stokes number, stability results for a finite Reynolds number and results for the inviscid flow bring together when augmenting the particle mass concentration at the wall. Therefore, by knowing single phase flow results and the evolution of stability characteristics of the two phase flow in the inviscid case, it it easy to determine whether particle-laden Taylor flow is more or less stable than the monophasic Taylor flow for large particle mass concentration. (authors)

  9. Mécanismes et fonctions de la voie d'ARN interférence induite par ARN double brin chez Paramecium tetraurelia

    OpenAIRE

    Carradec , Quentin

    2014-01-01

    The ciliate Paramecium tetraurelia is an interesting model to study the diversity and evolution of RNA interference (RNAi) pathways. One of the vegetative RNAi pathways is induced by feeding cells with bacteria producing double-stranded RNA (dsRNA) homologous to a given gene, which is then post-transcriptionally silenced through the production of 23-nt siRNAs. A forward genetic screen allowed us to obtain Mendelian mutants deficient in dsRNA-induced RNAi, and mutated genes were identified by ...

  10. Treatment of radioinduced skin burns by adult stem cells;Traitement des brulures cutanees radio-induites par cellules souches adultes

    Energy Technology Data Exchange (ETDEWEB)

    Lataillade, J.J.; Prat, M. [Hopital Militaire Percy, Centre de Transfusion Sanguine des Armees, Dept. Recherches et Therapies Cellulaires, 92 - Clamart (France); Gourmelon, P. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Fontenay-aux-Roses (France); Bey, E. [Hopital Militaire Percy, Service de Chirurgie Plastique, 92 - Clamart (France)

    2009-12-15

    In the area of skin injuries caused by ionizing radiations; the recent opportunity give us the the possibility to manage victims of radiation accidents with skin acute symptoms of irradiation. The approach of cell therapy developed for these patients could be in a second time, used for other types of injuries as thermal burns and the injuries linked to overexposure in radiotherapy. In spite of the diversity of approaches of allogeneic and autologous transplantation, the prognosis of deep and extended radioinduced burns is not completely satisfying because of inflammatory recurrences, origin of graft failures. The stem cells have been used in association. The stem cells were got from sampling of autologous bone marrow after an expansion in vitro from 15 to 17 days. The cultures were realised in medium with 8% of platelet lysate (clinical grade). The cells have been given by injection in complement of epidermis auto graft. A spectacular effect was noticed the day after the injection, but disappearing in some days encouraging to realize supplementary injections. An effect of the quickness and the quality of the graft success is appeared significant too. no necrosis recurrence for the patients after four years for the first one of them. We think that the stem cells participate to the local control of inflammation. (N.C.)

  11. It's quicker "Par Avignon"!

    CERN Multimedia

    2005-01-01

    For a few years, the CERN Library has been receiving books from the University of Hanover sent via Avignon, at least that's what it says on the envelope. Such a detour would mean that parcels were travelling 720 km more than the distance separating Geneva and Hanover, which would be a very strange state of affairs. The explanation lies in a spelling mistake. The sender has been stamping parcels with a stamp that says "Par Avignon prioritaire" (first-class via Avignon) instead of "Par Avion prioritaire" (First Class Air Mail), a source of much amusement to the librarians!

  12. Peptide-Based Optical uPAR Imaging for Surgery

    DEFF Research Database (Denmark)

    Juhl, Karina; Christensen, Anders; Persson, Morten

    2016-01-01

    Near infrared intra-operative optical imaging is an emerging technique with clear implications for improved cancer surgery by enabling a more distinct delineation of the tumor margins during resection. This modality has the potential to increase the number of patients having a curative radical...... tumor resection. In the present study, a new uPAR-targeted fluorescent probe was developed and the in vivo applicability was evaluated in a human xenograft mouse model. Most human carcinomas express high level of uPAR in the tumor-stromal interface of invasive lesions and uPAR is therefore considered...... an ideal target for intra-operative imaging. Conjugation of the flourophor indocyanine green (ICG) to the uPAR agonist (AE105) provides an optical imaging ligand with sufficiently high receptor affinity to allow for a specific receptor targeting in vivo. For in vivo testing, human glioblastoma xenograft...

  13. A practical contribution to the dosimetry of fast neutrons in radio-protection - determination of the integrated dose in man using the {sup 32}S(n, p){sup 32}P reaction (1963); Contribution pratique a la dosimetrie des neutrons rapides en radioprotection - determination de la dose integree par reaction {sup 32}S(n, p){sup 32}P chez l'homme (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Scheidhauer, J; Chabidon, M [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1963-07-01

    The problem of fast neutron dosimetry using activation is studied from the radio-protection point of view. The practical development of methods for analyzing phosphorus 32 produced by the activation of sulphur 32 in human hair by the reaction {sup 32}S(n, p){sup 32}P is described. The sensitivity obtained is 5 rad. A preliminary study was made of the variations in the natural sulphur and phosphorus concentrations. (authors) [French] Le probleme de la dosimetrie des neutrons rapides par activation est etudie sous l'angle de la radioprotectlon. Une mise au point pratique de methodes d'analyae du phosphore 32 induit par activation du soufre 32 des cheveux humains par reaction {sup 32}S(n, p){sup 32}P est exposee. La sensibilite obtenue est de 5 rad. Les variations du soufre et du phosphore naturels ont fait l'objet d'une etude preliminaire. (auteurs)

  14. La pelade par plaques

    Science.gov (United States)

    Spano, Frank; Donovan, Jeff C.

    2015-01-01

    Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre l’épidémiologie, la pathogenèse, l’histologie et l’approche clinique au diagnostic de la pelade par plaques. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant la pathogenèse, le diagnostic et le pronostic de la pelade par plaques. Message principal La pelade par plaques est une forme de perte pileuse auto-immune dont la prévalence durant une vie est d’environ 2 %. Des antécédents personnels ou familiaux de troubles auto-immuns concomitants, comme le vitiligo ou une maladie de la thyroïde, peuvent être observés dans un petit sous-groupe de patients. Le diagnostic peut souvent être posé de manière clinique en se fondant sur la perte de cheveux non cicatricielle et circulaire caractéristique, accompagnée de cheveux en « point d’exclamation » en périphérie chez ceux dont le problème en est aux premiers stades. Le diagnostic des cas plus complexes ou des présentations inhabituelles peut être facilité par une biopsie et un examen histologique. Le pronostic varie largement et de mauvais résultats sont associés à une apparition à un âge précoce, une perte importante, la variante ophiasis, des changements aux ongles, des antécédents familiaux ou des troubles auto-immuns concomitants. Conclusion La pelade par plaques est une forme auto-immune de perte de cheveux périodiquement observée en soins primaires. Les médecins de famille sont bien placés pour identifier la pelade par plaques, déterminer la gravité de la maladie et poser le diagnostic différentiel approprié. De plus, ils sont en mesure de renseigner leurs patients à propos de l’évolution clinique de la maladie ainsi que du pronostic général selon le sous-type de patients.

  15. Contribution to the study of detonation initiation by shock in solid explosives (1961); Contribution a l'etude de l'initiation de la detonation par choc dans les explosifs solides (1961)

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-05-15

    When a shock wave is induced in an explosive, it can initiate chemical reactions which lead more or less rapidly to a stable detonation state. In this study more particular attention was paid to the transition phase, in which has been evaluated the increases in the wave velocity, the pressure, and the electrical conductivity. The influence of the nature of the medium in front of the wave and in contact with the explosive has also been the subject of an experimental study designed to determine the extent to which its nature can be ignored and, subsequently, to characterise the initiation conditions using only the shock intensity induced in the explosive. Finally, the results were generalized for various explosive compositions and led to the development of a possible mechanism for shock initiation. (author) [French] Lorsqu'une onde de choc est induite dans un explosif, elle peut y amorcer des reactions chimiques qui conduisent plus ou moins rapidement a un regime de detonation stable. Dans cette etude, on s'est interesse plus particulierement a la phase transitoire dans laquelle on a evalue l'accroissement de la vitesse d'onde, de la pression et de la conductibilite electrique. L'influence du milieu amont, au contact de l'explosif, a egalement fait l'objet de recherches experimentales de facon a determiner dans quelle mesure on pouvait s'affranchir de sa nature et, par suite, caracteriser les conditions d'initiation par la seule intensite du choc induit dans l'explosif. Enfin, les resultats ont ete generalises a diverses compositions explosives et ont conduit a l'elaboration d'un schema possible du mecanisme de l'initiation par choc. (auteur)

  16. Contribution to the study of detonation initiation by shock in solid explosives (1961); Contribution a l'etude de l'initiation de la detonation par choc dans les explosifs solides (1961)

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-05-15

    When a shock wave is induced in an explosive, it can initiate chemical reactions which lead more or less rapidly to a stable detonation state. In this study more particular attention was paid to the transition phase, in which has been evaluated the increases in the wave velocity, the pressure, and the electrical conductivity. The influence of the nature of the medium in front of the wave and in contact with the explosive has also been the subject of an experimental study designed to determine the extent to which its nature can be ignored and, subsequently, to characterise the initiation conditions using only the shock intensity induced in the explosive. Finally, the results were generalized for various explosive compositions and led to the development of a possible mechanism for shock initiation. (author) [French] Lorsqu'une onde de choc est induite dans un explosif, elle peut y amorcer des reactions chimiques qui conduisent plus ou moins rapidement a un regime de detonation stable. Dans cette etude, on s'est interesse plus particulierement a la phase transitoire dans laquelle on a evalue l'accroissement de la vitesse d'onde, de la pression et de la conductibilite electrique. L'influence du milieu amont, au contact de l'explosif, a egalement fait l'objet de recherches experimentales de facon a determiner dans quelle mesure on pouvait s'affranchir de sa nature et, par suite, caracteriser les conditions d'initiation par la seule intensite du choc induit dans l'explosif. Enfin, les resultats ont ete generalises a diverses compositions explosives et ont conduit a l'elaboration d'un schema possible du mecanisme de l'initiation par choc. (auteur)

  17. Dynamic Filament Formation by a Divergent Bacterial Actin-Like ParM Protein.

    Directory of Open Access Journals (Sweden)

    Anthony J Brzoska

    Full Text Available Actin-like proteins (Alps are a diverse family of proteins whose genes are abundant in the chromosomes and mobile genetic elements of many bacteria. The low-copy-number staphylococcal multiresistance plasmid pSK41 encodes ParM, an Alp involved in efficient plasmid partitioning. pSK41 ParM has previously been shown to form filaments in vitro that are structurally dissimilar to those formed by other bacterial Alps. The mechanistic implications of these differences are not known. In order to gain insights into the properties and behavior of the pSK41 ParM Alp in vivo, we reconstituted the parMRC system in the ectopic rod-shaped host, E. coli, which is larger and more genetically amenable than the native host, Staphylococcus aureus. Fluorescence microscopy showed a functional fusion protein, ParM-YFP, formed straight filaments in vivo when expressed in isolation. Strikingly, however, in the presence of ParR and parC, ParM-YFP adopted a dramatically different structure, instead forming axial curved filaments. Time-lapse imaging and selective photobleaching experiments revealed that, in the presence of all components of the parMRC system, ParM-YFP filaments were dynamic in nature. Finally, molecular dissection of the parMRC operon revealed that all components of the system are essential for the generation of dynamic filaments.

  18. suPAR

    DEFF Research Database (Denmark)

    Eugen-Olsen, Jesper; Giamarellos-Bourboulis, Evangelos J

    2015-01-01

    Investigation of biomarkers that can promptly predict unfavourable outcome of critically illness is an emerging necessity taking into consideration the need for early intervention, the shortage of available beds in intensive care units and the considerable cost of hospitalisation. The most...... promising biomarker is soluble urokinase-type plasminogen activator receptor (suPAR). Three studies in large populations of critically ill patients and patients admitted to the emergency department have shown that concentrations >12ng/mL can safely predict unfavourable outcome. This review presents...

  19. New developments in the analysis and measurement of thicknesses by {beta}-particle excitation of X fluorescent rays; Nouveaux developpements de l'analyse et de la mesure des epaisseurs par excitation des raies de fluorescence X au moyen de particules {beta}; Novye usovershenstvovaniya analiza i izmereniya plotnosti putem vozbuzhdeniya fluorestsiruyushchikh spektrov rentgenovskogo lucha beta-chastitsami; Nuevos adelantos en el analisis y la medicion de espesores mediante la excitacion de rayos X por particulas beta

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, P [Commissariat a l' Energie Atomique, Saclay (France); Seibel, G [Institut de Recherches de la Siderurgie, St-Germain-en-Laye (France)

    1962-01-15

    The method of analysing and measuring the thickness of deposits by {beta}-X fluorescence which we previously described has been further developed. Using Pm{sup 147} and Kr{sup 85} sources, it is possible to reduce the background observed with Sr{sup 90}. We quote the results obtained for various thickness measurements of metal deposits, an analysis of the solutions, and the continuous measurement of calcium and iron in core samples. We describe experiments made for analysis of the X-radiation by crystal. (author) [French] Le procede d'analyse et de mesure des epaisseurs de depots par fluorescence {beta}-X que nous avons precedemment decrit a fait l'objet de nouveaux developpements. L'emploi de sources de {sup 147}Pm et de {sup 85}Kr permet de reduire le bruit de fond que l'on observe avec le {sup 90}Sr. Nous donnons les resultats obtenus pour diverses mesures d'epaisseurs de depots metalliques, l'analyse des solutions et la mesure en continu du calcium et du fer dans les carottes de minerais. Nous decrivons les essais effectues en vue d'analyser le rayonnement X au moyen d'un cristal. (author) [Spanish] Los autores han introducido nuevos perfeccionamientos en su procedimiento de analisis y de medicion de espesores de depositos por fluorescencia de rayos X excitada por particulas beta. La utilizacion de fuentes de {sup 147}Pm y de {sup 85}Kr permite reducir la actividad de fondo que se observa empleando {sup 90}Sr. Los autores exponen los resultados obtenidos en materia de mediciones de espesores de depositos metalicos, analisis de soluciones y medicion continua del calcio y del hierro en muestras de minerales extraidas por sondeo. Tambien describen los ensayos realizados con miras a analizar los rayos X por medio de un cristal. (author) [Russian] Protsess analiza i izmereniya plotnosti sloev putem fluorestsiruyushchikh beta- i rentgenovskikh luchej, kotoryj opisyvalsya nami ran'she, byl predmetom novykh usovershenstvovanij. Ispol'zovanie istochnikov prometeya-147 i

  20. Phénomènes neuro-inflammatoires au cours de l'état de mal épileptique induit par le soman. Correction par des combinaisons atropine-kétamine.

    OpenAIRE

    Dhote , Franck

    2010-01-01

    Epileptic seizures, status epilepticus (SE) and seizure-related brain damage (SRBD) due to organophosphorus nerve agent (OP) poisoning are accompanied by neuro-inflammatory events whose role in SRBD is not clear. Antagonists of the glutamatergic receptor NMDA, such as ketamine (KET), proved to be antiepileptic and neuroprotective even when SE is refractory to benzodiazepines 10 to 20 min after the initiation of seizures. Moreover, peripheral anti-inflammatory properties of KET have been descr...

  1. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ch

    2000-09-15

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

  2. Parálisis cerebral :

    OpenAIRE

    Cabrero Izquierdo, María del Carmen

    2012-01-01

    Se aborda el tema de la parálisis cerebral definiendo qué es, clasificando los tipos de parálisis dependiendo de la afectación y las características principales. Se explican algunos de sus tratamientos, se dan sistemas alternativos y/o aumentativos de comunicación para un alumno con PC (parálisis cerebral).

  3. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  4. Elastic and inelastic scattering of 2 to 10 MeV protons by lithium isotopes; Diffusion elastique et inelastique des protons de 2 a 10 MeV par les isotopes du lithium

    Energy Technology Data Exchange (ETDEWEB)

    Laurat, M [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    A description is given of the experimental set-up which has been devised for carrying out spectrometric and absolute cross-section measurements on the reactions induced by protons accelerated in a 12 MeV Van de Graaff Tandem. The particles are detected by silicon junctions; the weight of the targets (about ten {mu}g/cm{sup 2}) is determined by the quartz method. The experimental equipment has been controlled by a study of proton scattering by lithium-6, and has made it possible to evaluate the elastic and inelastic scattering (1. level excitation) by lithium 7 of 2 to 9 MeV protons. The most probable spin and parity values for the six levels of {sup 8}Be between 19 and 25 MeV excitation energy have been determined from a knowledge of the observed structure. (author) [French] Nous decrivons le dispositif experimental mis au point pour effectuer les mesures de spectrometrie et de section efficace absolue pour les reactions induites par des protons acceleres par un Van de Graaff Tandem 12 MeV. Les particules sont detectees par des jonctions au silicium, le poids des cibles (de l'ordre d'une dizaine de {mu}g/cm{sup 2}), mesure par la methode du quartz. L'ensemble de l'appareillage a ete controle par l'etude de la diffusion des protons par le lithium 6, et nous a permis de preciser les diffusions elastiques et inelastiques (excitation du 1er niveau) des protons de 2 a 9 MeV par le lithium 7. La structure observee a permis de determiner les spin et parite les plus probables de six niveaux du {sup 8}Be entre 19 et 25 MeV d'energie d'excitation. (auteur)

  5. Elastic and inelastic scattering of 2 to 10 MeV protons by lithium isotopes; Diffusion elastique et inelastique des protons de 2 a 10 MeV par les isotopes du lithium

    Energy Technology Data Exchange (ETDEWEB)

    Laurat, M. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    A description is given of the experimental set-up which has been devised for carrying out spectrometric and absolute cross-section measurements on the reactions induced by protons accelerated in a 12 MeV Van de Graaff Tandem. The particles are detected by silicon junctions; the weight of the targets (about ten {mu}g/cm{sup 2}) is determined by the quartz method. The experimental equipment has been controlled by a study of proton scattering by lithium-6, and has made it possible to evaluate the elastic and inelastic scattering (1. level excitation) by lithium 7 of 2 to 9 MeV protons. The most probable spin and parity values for the six levels of {sup 8}Be between 19 and 25 MeV excitation energy have been determined from a knowledge of the observed structure. (author) [French] Nous decrivons le dispositif experimental mis au point pour effectuer les mesures de spectrometrie et de section efficace absolue pour les reactions induites par des protons acceleres par un Van de Graaff Tandem 12 MeV. Les particules sont detectees par des jonctions au silicium, le poids des cibles (de l'ordre d'une dizaine de {mu}g/cm{sup 2}), mesure par la methode du quartz. L'ensemble de l'appareillage a ete controle par l'etude de la diffusion des protons par le lithium 6, et nous a permis de preciser les diffusions elastiques et inelastiques (excitation du 1er niveau) des protons de 2 a 9 MeV par le lithium 7. La structure observee a permis de determiner les spin et parite les plus probables de six niveaux du {sup 8}Be entre 19 et 25 MeV d'energie d'excitation. (auteur)

  6. par genes in Mycobacterium bovis and Mycobacterium smegmatis are arranged in an operon transcribed from "SigGC" promoters

    Directory of Open Access Journals (Sweden)

    Casart Yveth

    2008-03-01

    Full Text Available Abstract Background The ParA/Soj and ParB/Spo0J proteins, and the cis-acting parS site, participate actively in chromosome segregation and cell cycle progression. Genes homologous to parA and parB, and two putative parS copies, have been identified in the Mycobacterium bovis BCG and Mycobacterium smegmatis chromosomes. As in Mycobacterium tuberculosis, the parA and parB genes in these two non-pathogenic mycobacteria are located near the chromosomal origin of replication. The present work focused on the determination of the transcriptional organisation of the ~6 Kb orf60K-parB region of M. bovis BCG and M. smegmatis by primer extension, transcriptional fusions to the green fluorescence protein (GFP and quantitative RT-PCR. Results The parAB genes were arranged in an operon. However, we also found promoters upstream of each one of these genes. Seven putative promoter sequences were identified in the orf60K-parB region of M. bovis BCG, whilst four were identified in the homologous region of M. smegmatis, one upstream of each open reading frame (ORF. Real-time PCR assays showed that in M. smegmatis, mRNA-parA and mRNA-parB levels decreased between the exponential and stationary phases. In M. bovis BCG, mRNA-parA levels also decreased between the exponential and stationary phases. However, parB expression was higher than parA expression and remained almost unchanged along the growth curve. Conclusion The majority of the proposed promoter regions had features characteristic of Mycobacterium promoters previously denoted as Group D. The -10 hexamer of a strong E. coli σ70-like promoter, located upstream of gidB of M. bovis BCG, overlapped with a putative parS sequence, suggesting that the transcription from this promoter might be regulated by the binding of ParB to parS.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-05-15

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

  8. Thermal Annealing of Paramagnetic Defects Induced by Gamma Irradiation in (NH{sub 4}){sub 2}SO{sub 4} and (ND{sub 4}){sub 2}SO{sub 4} Single Crystals: Experimental Verification of the Theory of Fletcher and Brown; Recuit Thermique des Defauts Paramagnetiques Induits par Irradiation Gamma dans des Monocristaux de (NH{sub 4}){sub 2}SO{sub 4} et (ND{sub 4}){sub 2}SO{sub 4}: Verification Experimentale de la Theorie de Fletcher et Brown; 0422 0415 0420 041c 0414 ; Regeneracion Termica de los Defectos Paramagneticos Inducidos por Irradiacion Gamma en Monocristales de (NH{sub 4}){sub 2}SO{sub 4} y (ND{sub 4}){sub 2}SO{sub 4}: Verificacion Experimental de la Teoria de Fletcher y Brown

    Energy Technology Data Exchange (ETDEWEB)

    Calusaru, A.; Barbur, I.; Ursu, I. [Institut de Physique Atomique, Bucarest (Romania); Universite ' Babes' , Cluj (Romania)

    1965-04-15

    second 2,020, pour le sulfate d'ammonium avec hydrogene; les memes constantes pour le cristal deutere sont 1,9996 et 2,0032. L'etude du recuit du premier radical pour des temperatures comprises entre 60 Degree-Sign et 170 Degree-Sign C a montre qu'il y a dans ce cas une cinetique a un seul plateau correspondant a une recombinaison totale des radicaux. Il a ete possible d'etablir une equation pour chaque isotherme, en utilisant la fonction des erreurs deduite par Fletcher et Brown, et en prenant pour modele la recombinaison, selon un processus aleatoire (random-walk process), des paires initialement conelees, puis liberees. L'accord entre cette fonction et l'experience a ete obtenu apres correction de cette fonction par un facteur a. La courbe de recuit ainsi etablie verifie tres bien la fonction des erreurs corrigee. En appliquant la methode phenomenologique de Fletcher et Brown pour le calcul de l'energie d'activation, on a trouve la valeur 1,594 eV, qui correspond au premier radical en (NH{sub 4}){sub 2}SO{sub 4}. En utilisant la variation du coefficient de diffusion en fonction de la temperature, on a obtenu pour la meme energie d'activation la valeur 1,592 eV. Par la methode de Vand-Primack on a trouve la valeur 1,45 eV, qui est plus petite que les deux precedentes. On a considere, en conclusion, que le modele de la recombinaison des paires correlees d'apres un processus aleatoire est applicable dans la forme donnee par la theorie lorsqu'il y a une assez faible interaction entre le reseau et les especes formees-, de cette maniere les paires initialement correlees peuvent se liberer. (author) [Spanish] En cristales de (NH{sub 4}){sub 2}SO{sub 4} y (ND{sub 4}){sub 2}SO{sub 4}, sometidos a irradiacion, se han identificado dos especies paramagneticas aplicando el metodo de resonancia del espfn electronico. La constante g del primer radical es de 2,014 y la del segundo de 2,020, para el (NH{sub 4}){sub 2}SO{sub 4}; en el caso del cristal deuterado, dichas constantes son 1

  9. Elusloom lennukiga puhkusele / Inge Parring

    Index Scriptorium Estoniae

    Parring, Inge

    2003-01-01

    Ilmunud ka: Delovõje Vedomosti 1. okt. lk. 13. Air Cargo Estonia/ACE Logisticsi müügijuht Inge Parring tutvustab elusloomade transpordivõimalusi. Vt. samas: Loomade transportimiseks vajalikud dokumendid

  10. Par Pond vegetation status 1996

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1996-12-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995, and into the early spring and late summer of 1996. Communities similar to the pre-drawdown, Par Pond aquatic plant communities continue to become re-established. Emergent beds of maidencane, lotus, waterlily, watershield, and Pontederia are extensive and well developed. Measures of percent cover, width of beds, and estimates of area of coverage with satellite data indicate regrowth within two years of from 40 to 60% of levels prior to the draw down. Cattail occurrence continued to increase during the summer of 1996, especially in the former warm arm of Par Pond, but large beds common to Par Pond prior to the draw down still have not formed. Lotus has invaded and occupies many of the areas formerly dominated by cattail beds. To track the continued development of macrophytes in Par Pond, future surveys through the summer and early fall of 1997, along with the evaluation of satellite data to map the extent of the macrophyte beds of Par Pond, are planned

  11. The determination of iodine in biological media using radioactivation analysis (1962); Dosage de l'iode dans les milieux biologiques au moyen de l'analyse par radioactivation (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-06-15

    The object of this study is to show that the application of radioactivation analysis to the determination of iodine in biological media makes it possible to measure iodine concentrations of the order of 0.0001 {mu}g. After a review of the chemical methods with a mention of the difficulties they present, the optimum conditions for the determination of iodine in biological liquids are given. Three methods are described: - the first consists of a chemical treatment which liberates the protein bound iodine in an inorganic form. After distillation this iodine is irradiated in a flux of thermal neutrons. The induced radioactivity is compared to that of a standard sample irradiated in the same conditions by {gamma} spectrometry. - the second method which is of more general application consists in irradiating the sample and then extracting the iodine; its induced radio-activity is then measured by {beta}-counting. - the third method measures the iodine directly in the thyroid tissue by anti-compton spectrometry. The sensitivity, the reproducibility and the accuracy are discussed. Some applications are described: determination of iodine in its various organic forms in serum, determination of iodine in urines, in food-stuffs, etc., in the thyroid tissue, etc. (author) [French] Le but de cette etude est de montrer que l'analyse par radioactivation appliquee au dosage de l'iode dans les milieux biologiques permet de mesurer des taux d'iode de l'ordie de 0,0001 {mu}g. Apres avoir rappele le principe des methodes chimiques et montre les difficultes de leur mise en oeuvre, il est etabli les conditions optima pour realiser le dosage de l'iode dans les liquides biologiques. Trois methodes sont decrites; - la premiere consiste a pratiquer un traitement chimique liberant l'iode proteique sous forme minerale. Apres distillation cet iode est irradie dans un flux de neutrons thermiques. La radioactivite induite est mesuree comparativement a celle d'un etalon traite dans les memes

  12. Vote par sondage uniforme incorruptible

    OpenAIRE

    Blanchard , Nicolas

    2016-01-01

    International audience; Introduit en 2012 par David Chaum, le vote par sondage uniforme (random-sample voting) est un protocole de vote basé sur un choix d'une sous-population représentative , permettant de limiter les coûts tout en ayant de nombreux avantages, principalement lorsqu'il est couplé a d'autres techniques comme ThreeBallot. Nous analysons un problème de corruptibilité potentielle où les votants peuvent vendre leur vote au plus offrant et proposons une variation du protocole reméd...

  13. Some applications of neutron activation analysis in plant biology and agronomy; Quelques applications de l'analyse par radioactivation neutronique en biologie vegetale et en agronomie

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-06-01

    Plants materials are not so commonly analysed by radioactivation than biological extracts of medical importance. With help of concrete examples, applications of neutrons activation analysis to the determination of some metals (Mn, Cu, Co, Fe, Zn, and K) in plant materials, are proposed. Samples are activated in a swimming-pool reactor at the thermal flux of 5.10{sup 12} n.cm{sup -2}s{sup -1} for a time varying between few minutes and several days according to the element being analysed. The induced radioactivity is measured by spectrometry, with radiochemical separation ( Cu, Co, Fe, Zn and K) or without separation in best cases (Mn,Cu, K). Described dosages are related to: manganese in a graminaceous plant, copper in vine treatments, cobalt, iron and zinc in animal feeding, potassium in a radiological experiment. (author) [French] Les produits vegetaux sont beaucoup moins souvent soumis a l'analyse par activation que les extraits biologiques d'interet medical. En s'appuyant sur des cas concrets, nous proposons des applications de l'analyse par activation neutronique au dosage de differents metaux (Mn, Cu, Co, Fe, Zn, et K) dans la matiere vegetale. Les echantillons sont actives en pile piscine au flux thermique de 5.10{sup 12} n.cm{sup -2} s{sup -1} pendant des temps variant de quelques minutes a plusieurs jours selon les elements a analyser. le comptage de la radioactivite induite est effectue par spectrometrie gamma apres separation radiochimique (Cu, Co, Fe, Zn, et K) ou sans separation dans les cas favorables (Mn, Cu, K). Les dosages decrits concernent: le manganese dans une graminee, le cuivre en viticulture, le cobalt, le fer, et le zinc dans un aliment du betail, le potassium dans une experience de radioecologie. (auteur)

  14. A mechanism for ParB-dependent waves of ParA, a protein related to DNA segregation during cell division in prokaryotes

    DEFF Research Database (Denmark)

    Hunding, Axel; Gerdes, Kenn; Charbon, Gitte Ebersbach

    2003-01-01

    in an autocatalytic process. We discuss this mechanism in relation to recent models for MinDE oscillations in E.coli and to microtubule degradation in mitosis. The study points to an ancestral role for the presented pattern types in generating bipolarity in prokaryotes and eukaryotes.......Prokaryotic plasmids encode partitioning (par) loci involved in segregation of DNA to daughter cells at cell division. A functional fusion protein consisting of Walker-type ParA ATPase and green fluorescent protein (Gfp) oscillates back and forth within nucleoid regions with a wave period of about...

  15. Par Pond Fish, Water, and Sediment Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

  16. Par Pond Fish, Water, and Sediment Chemistry

    International Nuclear Information System (INIS)

    Paller, M.H.; Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

  17. Fluorescence microscopy.

    Science.gov (United States)

    Sanderson, Michael J; Smith, Ian; Parker, Ian; Bootman, Martin D

    2014-10-01

    Fluorescence microscopy is a major tool with which to monitor cell physiology. Although the concepts of fluorescence and its optical separation using filters remain similar, microscope design varies with the aim of increasing image contrast and spatial resolution. The basics of wide-field microscopy are outlined to emphasize the selection, advantages, and correct use of laser scanning confocal microscopy, two-photon microscopy, scanning disk confocal microscopy, total internal reflection, and super-resolution microscopy. In addition, the principles of how these microscopes form images are reviewed to appreciate their capabilities, limitations, and constraints for operation. © 2014 Cold Spring Harbor Laboratory Press.

  18. Directed and persistent movement arises from mechanochemistry of the ParA/ParB system.

    Science.gov (United States)

    Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

    2015-12-22

    The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos-an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

  19. Recherche documentaire par titrage automatique

    OpenAIRE

    Lopez , Cédric; Prince , Violaine; Roche , Mathieu

    2011-01-01

    Nous proposons dans cet article un système facilitant la recherche d'information dans un ensemble de documents textuels, basé sur le titrage (et sous-titrage) automatique. Ce dernier peut se révéler crucial, par exemple, dans le cadre de la problématique de l'accessibilité des pages web (norme W3C). Notre processus de titrage automatique consiste à extraire des syntagmes nominaux pertinents dans les textes, pouvant constituer des titres ou sous-titres candidats. Une approche originale combina...

  20. Characterization of ionizing radiation effects in MOS structures by study of bipolar operation; Caracterisation des effets induits par irradiations ionisantes dans des structures MOS a partir de leur fonctionnement en regime bipolaire

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtiar, H. [Univ. Teknologi Malaysia, Dept. of Physics, Johor (Malaysia); Picard, C.; Brisset, C. [CEA Saclay, Lab. d' Electronique et de Technologie de l' Informatique, LETI, 91 - Gif-sur-Yvette (France); Bakhtiar, H.; Hoffmann, A.; Charles, J.P. [Metz Univ., LICM-CLOES-Supelec, 57 (France)

    1999-07-01

    This work presents an original method to characterize radiation effects of micronic transistors. The characterization includes a study of the transistor substrate-drain junction and current gain variation of the bipolar transistor (drain-substrate-source as emitter-base-collector) for different gate voltages. (author000.

  1. Pathologies des hélicases et vieillissement précoce : modèle d'étude par dérivation de cellules souches pluripotentes induites (iPS)

    OpenAIRE

    Gatinois , Vincent

    2017-01-01

    Helicases process the double-stranded DNA dissociation. They are involved in replication, DNA repair and maintenance of telomeres. In human, 3 helicases display mutations responsible for clinical syndromes: WRN for the Werner syndrome, BLM for the Bloom syndrome and RECQL4 for the Rothmund-Thomson syndrome. All these diseases cause premature ageing and high risk of cancer. Molecular and cellular mechanisms involved in these diseases are not well defined. Particularly, little is known concerni...

  2. Sub-micron indent induced plastic deformation in copper and irradiated steel; Deformation plastique induite par l'essai d'indentation submicronique, dans le cuivre et l'acier 316L irradie

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Ch

    1999-07-01

    In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu (001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg. C - 600 deg. C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM identified clusters seems not to be affected by such thermal treatment. In order to rationalize these results, we suggest that krypton irradiation induced hardening is produced by defect clusters more unstable and smaller than those mentioned. (author)

  3. Alteration of the digestive motility linked with radiation-induced inflammatory processes in rats; Alterations de la motricite digestive associees aux processus inflammatoires induits par les rayonnements ionisants chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Picard, C

    2000-12-01

    Exposure to ionizing radiation, whether accidental or for medical reasons, may lead to gastro-intestinal injury, characterized by nausea, vomiting, diarrhea and abdominal cramps. The aetiology of radiation-induced diarrhea remains to date unclear. In this study, we have investigated the acute effects of a 10 Gy abdominal irradiation on rat digestive functions. The objective of the first study was to evaluate the role of sensory afferent neurons, capsaicin-sensitive, on morphological changes and the inflammatory response following exposure. Three days after irradiation, we observed an inflammatory response characterized by neutrophils infiltration and mast cells de-granulation. No effect of capsaicin pre-treatment was seen on these parameters. However, neutrophils infiltration was increased as early as one day after irradiation in capsaicin-treated rats. No difference in severity of diarrhea was observed after denervation nor in morphological changes. These data demonstrate that abdominal irradiation results in diarrhea concomitant with an inflammatory response, and that sensory innervation does not play a major protective role. The objective of the rest of the work was in the first instance to characterize radiation-induced alterations of intestinal and colonic motility leading to diarrhea and secondly to evaluate the role of serotonin in such disorders. Perturbations in intestinal (MMC) and colonic (LSB) motor profiles were observed from the first day onwards. Migrating motor complexes (MMC) were completely disrupted at three days at the same time as the onset of diarrhea. In addition to inhibition of LSB, colonic fluid absorptive capacity was decreased and serotonin colonic tissue levels were increased three days after irradiation. Radiation-induced diarrhea was reduced by treatment with an antagonist of 5-HT{sub 3} receptors, granisetron, as were alterations of colonic motility and serotonin tissue levels. However, this treatment did not significantly ameliorate fluid absorption on three days. These two studies show that a 10 Gy abdominal irradiation markedly affects intestinal and colonic motility both of which contribute to the ensuing diarrhea, and a role for serotonin via 5-HT{sub 3} receptors. In conclusion, these results demonstrate functional modifications without marked alterations of intestinal and colonic morphology. These changes are concomitant with an inflammatory response which does not appear to involve afferent nerves. However, serotonin plays an important role in the inhibition of colonic motility and in consequence in the establishment of diarrhea. (author)

  4. Muscular fixing of the H.M.D.P. {sup 99m}Tc induced by a statin, rosuvastatin or crestor: clinical case; Fixation musculaire du HMDP Tc99m induite par une statine, la rosuvastatine ou Crestor: cas clinique

    Energy Technology Data Exchange (ETDEWEB)

    Bourahla, K.; Hassler, S.; Schneegans, O.; Gyen, L.N. [CLCC Paul-Strauss, Service de medecine nucleaire, 67 - Strasbourg (France)

    2010-07-01

    Myositis induced by statins in treatment for hypercholesterolemia is a special clinical entity that may be encountered during an exploration by bone scintigraphy. We present the case of a muscle fixing observed in bone scan in a patient treated with rosuvastatin (Crestor). Muscular extra bone fixing of hydroxy-methane diphosphonate (H.M.D.P.) {sup 99m}T in patients referred for staging of prostate carcinoma, patients sometimes also treated for high cholesterol may be iatrogenic due to taking statins. A simple history may then allow its identification, although it remains asymptomatic. (N.C.)

  5. Ionisation and dissociation of water induced by swift multicharged ions; Etude de l'ionisation et de la dissociation d'H{sub 2}O induites par collision avec des ions multicharges rapides

    Energy Technology Data Exchange (ETDEWEB)

    Legendre, S

    2006-02-15

    Ionization and dissociation of water molecules and water clusters induced by 11.7 MeV/A Ni{sup 25+} ions were carried out by imaging techniques. Branching ratios, ionisation cross sections and Kinetic Energy Released distributions have been measured together with fragmentation dynamics studies. Multiple ionization represents approximately 30% of the ionizing events. Double ionization produces in significant way atomic oxygen, considered as a possible precursor of the large production of HO{sub 2} radical in liquid water radiolysis by ions of high Linear Energy Transfer. We evidence a strong selectivity of bond breakage in the case of ion-induced HOD fragmentation. Once the molecule doubly ionized, the breakage of the O-H bond is found 6.5 times more probable than that of the O-D bond. A semi-classical calculation simulating the fragmentation dynamics on the potential energy surface of the ground-state of di-cation H{sub 2}O{sup 2+} makes possible to as well reproduce the preferential nature of the breakage of the O-H bond as the position and the shift of the kinetic energy distributions. First results concerning interaction with water clusters are also reported. Measurements in coincidence are carried out giving access to correlation, with the distributions in energy and angle of the emitted fragments. Mass spectrum points fast intra-cluster proton transfer, leading to the emission of protonated clusters. (author)

  6. Etude du comportement sexuel mâle induit par la testostérone chez des brebis adultes ovariectomisées. Effet de la dose et de l'expérience sexuelle antérieure

    OpenAIRE

    Fabre-Nys, Claude; Signoret, Jean-Pierre; Garnier, Danielle; Lavenet, Colette; Orgeur, Pierre; Poirier, Jean-Claude; Venier, Gérard

    1983-01-01

    Adult ovariectomized ewes, daily injected with testosterone propionate (2 to 22 mg), showed male-like sexual behaviour, never seen in untreated females, but very similar to that in normal rams. After a few days of latency (3 days minimum), this behaviour gradually appeared and increased in frequency until a plateau was reached. The time-course in which the plateau was reached depended on the androgen dose and on previous experience with male sexual behaviour. Some male-like behaviour might...

  7. Electron emission following collisions between multi-charged ions and D{sub 2} molecules; Etude de l'emission electronique induite par impact d'ion multicharge sur la molecule D{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, G

    2004-05-15

    Dissociative ionisation mechanisms induced in collisions involving a highly charged ion (S{sup 15+}, 13.6 MeV/u) and a molecular deuterium target, have been studied through momentum vector correlations of both the D{sup +} fragments and the electrons produced. An experimental apparatus has been developed in order to detect in coincidence all the charged particles produced during the collision. The measurement of their momentum vectors, which allows one to determine both their kinetic energy and direction of emission with respect to the projectile one, combines Time of Flight, Position Sensitive Detection, and multi-coincidence techniques. The correlation of the fragment and electron kinetic energies enables not only to determine branching ratios between the dissociative ionisation pathways, but also to separate unambiguously kinetic energy distributions of fragments associated to each process. Finally, the angular distributions of ejected electrons, as a function of the orientation of the molecular axis with respect to the projectile direction, are deduced from the spatial correlation. Measurements are compared to theoretical angular distributions obtained using the CDW-EIS (Continuum Distorted Wave-Eikonal Initial State) method. (author)

  8. MUST, a set of strip detectors for studying radioactive beams induced reactions; MUST, un ensemble de detecteurs a pistes pour l`etude des reactions induites par faisceaux radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Blumenfeld, Y.; Barbier, A.; Beaumel, D.; Charlet, D.; Clavelin, J.F.; Douet, R.; Engrand, M.; Lebon, S.; Lelong, P.; Lesage, A.; Leven, V.; Lhenry, I.; Marechal, F.; Petizon, L.; Pouthas, J.; Richard, A.; Rougier, D.; Soulet, C.; Suomijaervi, T.; Volkov, P.; Voltolini, G. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Auger, F.; Ottini, S.; Alamanos, N. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Sauvestre, J.E.; Bonnereau, B.; Champion, L.; Delbourgo-Salvador, P.; Ethvignot, T.; Szmigiel, M. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France)

    1996-12-31

    This report states the specificity of light particles elastic scattering, and the need of detecting recoil protons to improve angular resolution. Then the development of a specific MUST strip detector is detailed: 60 strips detectors with Si O sub 2 dielectric, that yield 500 ps time resolution, and Si (Li) detectors following next. A versatile data acquisition system has been developed too, with CAMAC interface to suit to any experimental plant. (D.L.). 27 refs.

  9. Apoptosis induced by chlormethine and ionizing radiations in normal and tumoral lymphocytes: role of caspase-3; Apoptose induite par la chlormethine et les radiations ionisantes dans les lymphocytes normaux et tumoraux: role de la caspase-3

    Energy Technology Data Exchange (ETDEWEB)

    Holl, V.P

    2000-07-01

    Apoptosis can be induced by various stimuli like ionizing radiations or alkylating agents. Recent works have shown that apoptosis due to ionizing radiations can be initiated by DNA and cell membrane alterations, via radical species generation, implying the in fine activation of effector caspases, and in particular caspase-3. The main goal of this work is to clarify the role of caspase-3 in the radio-induced apoptosis mechanisms and to study the effects of apoptosis inhibition on the behaviour of the damaged cells. The effects of activation and caspase-3 activity inhibition on the progress of spontaneous, radio-induced or chlormethine-induced apoptosis have been evaluated for normal and tumoral lymphocytes. A chemical molecule, the ebselen, which can mime the action of the endogenous glutathione peroxidase, and a tetra-peptide inhibitor, AC-DEVD-CHO, selective of effector caspases, have been selected. The results indicate an inhibition by ebselen of all morphological and biochemical characteristics of chlormethine-induced apoptosis and a restoring of the cells viability. This seleno-organic compound also reduces the drop of the intra-cellular glutathione level and the loss of the trans-membrane potential (M) of the mitochondrion in the MOLT-4 tumoral cells treated with chlormethine. In parallel, the AC-DEVD-CHO effect on apoptosis induction has been tested. This inhibitor stops some chlormethine-induced criteria of apoptosis without affecting the final loss of the mitochondrial M and the cells proliferation. AC-DEVD-CHO has been also incubated just before the irradiation of the culture cells. The inhibition of the specific DEVD caspases prevents the inter-nucleosomal fragmentation of DNA and partially delays the externalization of phosphatidylserine without changing the viability of the irradiated cells. Moreover, the analysis of the AC-DEVD-CHO pre-treated irradiated cells floating on the surface shows a strong mitochondrial lactate dehydrogenase activity, which indicates the presence of organelles damage and a loss of the integrity of the plasmic membrane, i.e. two criteria of necrosis death. These results show that the apoptosis/necrosis conversion can be obtained after an irradiation and raises the question of its interest in radiotherapy. (J.S.)

  10. Gamma irradiation-induced modifications of resins found in nuclear waste embedding processes; Modifications induites par irradiation gamma dans les differentes resines rencontrees dans le traitement des dechets nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Allali, H [Faculte des Science et Techniques, Settat (Morocco); Debre, O; Lambert, M; Nsouli, B; Thomas, J P [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France); Collaboration: IPN-Lyon, Laboratoire d` Etude des Materiaux Plastiques et des Biomateriaux, URA 507, UCBL, Agence Nationale pour la Gestion des Dechets Radiactifs

    1999-12-31

    The various resins involved in nuclear waste disposal are subject to gamma irradiation-induced modifications. From Time-of-Flight Mass Spectrometry of Secondary ions emitted under High Energy Projectiles bombardment (HSF-SIMS) of such materials the following results are obtained: the embedding epoxy resin DGEBA-DDM does not exhibit significant bulk changes in chemical structure, whatever the dose rate and irradiation medium (air or water), at least up to 2 MGy. However, oxidation processes are well observed at the very surface. Under the same conditions Ion exchange resins to be embedded are subjected to scissions of their functional sites, leading to fixed ion release. Dehydration under irradiation is observed pointing out the crucial role of water in ion transport outside of the material. (authors)

  11. Localized corrosion of carbon steels due to sulfate-reducing bacteria. Development of a specific sensor; Corrosion localisee des aciers au carbone induite par des bacteries sulfato-reductrices. Developpement d'un capteur specifique

    Energy Technology Data Exchange (ETDEWEB)

    Monfort Moros, N.

    2001-11-01

    This work concerns the microbiologically influenced corrosion of carbon steels in saline anaerobic media (3% of NaCl) containing sulfato-reducing bacteria (Desulfovibrio gabonensis, DSM 10636). In these media, extreme localised corrosion occurs by pitting under the bio-film covering the metallic substrate. A sensor with concentric electrodes was designed to initiate the phenomenon of bio-corrosion, recreating the favourable conditions for growth of a corrosion pit, and then measuring the corrosion current maintained by bacterial activity. The pit initiation was achieved through either of two methods. The electrochemical conditioning involved driving the potential difference between inner and outer electrodes to values corresponding to a galvanic corrosion that can be maintained by the bacterial metabolism. The mechanical process involved removal of a portion of the bio-film by scratching, yielding galvanic potential differences equivalent to that found by the conditioning technique. This protocol was found to be applicable to a bio-corrosion study on industrial site for the monitoring of the metallic structures deterioration (patent EN 00/06114, May 2000). Thereafter, a fundamental application uses the bio-corrosion sensor for Electrochemical Impedance Spectroscopy (EIS), Electrochemical Noise Analysis (ENA) and current density cartography by the means of micro-electrodes. Thus, the EIS technique reveals the importance of the FeS corrosion products for initiation of bio-corrosion start on carbon steel. In addition, depending on the method used to create a pit, the ENA gives rise to supplementary processes (gaseous release) disturbing the bio-corrosion detection. The beginning of a bio-corrosion process on a clean surface surrounded with bio-film was confirmed by the current density cartography. These different results establish the sensor with concentric electrodes as an indispensable tool for bio-corrosion studies, both in the laboratory and on industrial sites. (author)

  12. Study of the neutron background noise generated by muons in the Edelweiss-2 experiment; Etude du bruit de fond neutron induit par les muons dans l'experience EDELWEISS-2

    Energy Technology Data Exchange (ETDEWEB)

    Chabert, L

    2004-07-01

    This thesis contributes to the Edelweiss experiment whose aim is to detect interactions between neutralinos and target nuclei. Bolometers used in Edelweiss combine the detection of phonons with the detection of electric charges generated by the energy deposition. This double detection enables us to discard background signals due to electronic interactions and soon detection sensitivity of the experiment will be limited by the neutron background noise due to residual cosmic muons. This work is dedicated to a detailed study of muon inelastic interactions and the consequent production of neutrons. Simulations show that the expected neutron flux is so high that the direct detection of muons is required in order to link it to the neutron signal issued by the bolometer. Results from simulations show that plastic scintillators might be the main components of the muon detector.

  13. Characterisation in vivo of ways of induced deaths by p53, in the male germinal cells; Caracterisation in vivo des voies de mort induites par la p53, dans les cellules germinales males

    Energy Technology Data Exchange (ETDEWEB)

    Coureuil, M

    2006-10-15

    The male germinal cells constitute a heterogeneous cell population including pre-meiotic proliferating cells (spermatogonia) and meiotic cells and post meiotic cells in differentiation (spermatocytes and spermatids). We study the involvement in vivo of the p53 protein in the death of these cells with the help of two models, (1) a transgenic model of infertility, MTp53, in which the p53 is over expressed in the differentiated cells and induced their death, (2) the response of these cells to gamma irradiation, where only the spermatogonia die by apoptosis dependent of p53. We showed that the caspases (cysteine-aspartic proteases) are involved in the terminal differentiation of normal germinal cells. But in the MTp53 model, the p53 induces the death of differentiated cells via the activation of calpains and not of caspases. We studied the response of spermatogonia, to gamma irradiation by a transcriptomic approach, by DNA chips and semi-quantitative RT-PCR. we showed that the puma and dr5 genes are induced by the p53 after irradiation. more, the study of mice invalidated for trail ( the dr5 ligand) or for puma, allowed to demonstrate that the two effectors are essential to the activation of intrinsic and extrinsic ways of apoptosis. (N.C.)

  14. Conception et développement d'outils immunologiques pour suivre et caractériser les réponses immunitaires induites par les vaccins contre l'allergie

    OpenAIRE

    Wambre , Eric

    2008-01-01

    Type I allergy either results from a pathological inappropriate Th2 immune response or from the defective induction of immune tolerance to otherwise harmless antigen : the allergen. Recent advances have underlined the major role played by allergen-specific CD4+ T cells in the control of allergic response. However, immunological mechanisms involved remain to be better documented and could provide important information regarding peripheral tolerance induction observed in healthy individuals. Ex...

  15. SECHAGE DE PRODUITS GRANULAIRES PAR DESHYDRATATION PAR DETENTES SUCCESSIVES (DDS)

    OpenAIRE

    Abdulla , Galal; Mellouk , Hamid; Belghit , Abdelhamid; Allaf , Karim

    2009-01-01

    International audience; Dans cette étude, nous avons évalué les performances d'un nouveau procédé de séchage dans le cas du liège en granulés. Ce procédé (La déshydratation par détentes successives : DDS) consiste à soumettre le matériau liège dans une chambre hermétique aux variations cycliques de la pression. Chaque cycle est composé d'une compression et d'une décompression. La phase de compression est réalisée en injectant de l'air comprimé à température ambiante provenant d'un compresseur...

  16. Molecular mechanism of bundle formation by the bacterial actin ParM

    Energy Technology Data Exchange (ETDEWEB)

    Popp, David, E-mail: dpopp@imcb.a-star.edu.sg [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore); Narita, Akihiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Iwasa, Mitsusada [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Maeda, Yuichiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Robinson, Robert C. [Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore)

    2010-01-22

    The actin homolog ParM plays a microtubule-like role in segregating DNA prior to bacterial cell division. Fluorescence and cryo-electron microscopy have shown that ParM forms filament bundles between separating DNA plasmids in vivo. Given the lack of ParM bundling proteins it remains unknown how ParM bundles form at the molecular level. Here we show using time-lapse TIRF microscopy, under in vitro molecular crowding conditions, that ParM-bundle formation consists of two distinct phases. At the onset of polymerization bundle thickness and shape are determined in the form of nuclei of short helically disordered filaments arranged in a liquid-like lattice. These nuclei then undergo an elongation phase whereby they rapidly increase in length. At steady state, ParM bundles fuse into one single large aggregate. This behavior had been predicted by theory but has not been observed for any other cytomotive biopolymer, including F-actin. We employed electron micrographs of ParM rafts, which are 2-D analogs of 3-D bundles, to identify the main molecular interfilament contacts within these suprastructures. The interface between filaments is similar for both parallel and anti-parallel orientations and the distribution of filament polarity is random within a bundle. We suggest that the interfilament interactions are not due to the interactions of specific residues but rather to long-range, counter ion mediated, electrostatic attractive forces. A randomly oriented bundle ensures that the assembly is rigid and that DNA may be captured with equal efficiency at both ends of the bundle via the ParR binding protein.

  17. Micro-ion beam analysis of physico-chemical reactions in vitro induced by nano-structured sol-gel derived bioactive glasses; Caracterisation par micro-faisceau d'ions des reactions physico-chimiques induites in vitro par des verres bioactifs nanostructures elabores par la methode sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Lao, J

    2007-07-15

    The study of bioactive glasses is a multi-field area of research aiming at a major goal: the development of new generation biomaterials that would be able to bond with host tissues through the formation of a strong interfacial bond, together with helping the body heal itself through the stimulation of specific cellular responses. Thus clinical applications of bioactive glasses mainly concern dental surgery and orthopedics, for filling osseous defects. For this purpose, we have elaborated bioactive glasses in the binary SiO{sub 2}-CaO system, ternary SiO{sub 2}-CaO-P{sub 2}O{sub 5} system, and for the first time, to our knowledge, strontium-doped SiO{sub 2}-CaO-SrO and SiO{sub 2}-CaO-P{sub 2}O{sub 5}-SrO glasses. The materials were elaborated using the sol-gel process, which allowed the synthesis of nano-porous materials with great purity and homogeneity. The bio-activity of the glasses was clearly demonstrated in vitro: in contact with biological fluids, the whole lot of mate-rials were able to induce the formation of a Ca-P-Mg layer a few microns thick at their surface. Our work is characterized by the use of PIXE-RBS nuclear microprobes to study the bioactive glass/biological fluids interface. Thanks to these methods we obtained chemical maps that made possible the analysis of major and trace elements concentrations at the interface. Moreover, quantitative information regarding the local reactivity of glasses were acquired. These data are important to evaluate the kinetics and amplitude of the physico-chemical reactions involved in the bio-activity process. Thus, we highlighted that the binary glass is the highest reactive regarding the dissolution of the glassy matrix as well as the first appearance of the Ca-P rich layer. However the Ca/P atomic ratio calculated at the glass/biological fluids interface decreases slowly, indicating that the Ca-P-Mg layer encounters difficulties to be changed into a more stable apatitic phase. For the P-containing glasses, the de-alkalinization of the matrix and the formation of the calcium phosphate layer are delayed. However, calculation of the interfacial Ca/P ratios along with supersaturation studies of the biological medium demonstrate that the Ca-P-Mg layer is quickly changed into an apatitic phase. Concerning the Sr-doped glasses, we highlighted that the dissolution of the material decreased and that the Ca-P-Mg layer was formed on a reduced depth. Nevertheless, according to the rapid decrease of the Ca/P ratio, there is evidence that the layer is more quickly changed into apatite, We also demonstrated that traces of Sr are both present at the glass/biological fluids interface and diffused in the biological medium. Knowing the positive effects of Sr on the cellular activity and on the bone modelling process, it might result in an improved bio-activity for the Sr-doped glasses in contact with a living system. (author)

  18. La preuve par le nombre

    Directory of Open Access Journals (Sweden)

    Hélène Verdier

    2012-04-01

    Full Text Available S’il en était besoin, la question des usages et de la finalité des résultats de l’inventaire général pourrait être abordée par le nombre : nombre d’œuvres répertoriées, de communes inventoriées, de clichés photographiques réalisés, de dossiers, de consultations des notices dans les bases de données… Les additions aujourd’hui sont éloquentes, mais elles laissent dans l’ombre le rôle de l’inventaire qui, en mettant en œuvre une démarche systématique de connaissance, participe à l’ identificatio...

  19. Use of gamma spectroscopy in activation analysis; Utilisation de la spectrographie gamma dans l'analyse par activation

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    Brief review of the principles of activation analysis: calculation of activities, decay curves, {beta} absorption curves, examples of application. - Principle and description of the {gamma} spectrograph. - Practical utilisation of the {gamma} spectrograph: analysis by activation, analysis by {beta} - x fluorescence. - Sensitivity limit of the method and precision of the measurements. - Possible improvements to the method: {gamma} spectroscopy with elimination of the Compton effect. (author) [French] Bref rappel des principes de l'analyse par activation: calcul des activites, courbes de decroissance, courbes d'absorption {beta}, exemples d'utilisation. - Principe et description du spectrographe {gamma}. - Utilisation pratique de la spectrographie {gamma}: analyse par activation, analyse par fluorescence {beta} - x. - Limite de sensibilite de la methode et precision des mesures. - Ameliorations possibles de la methode: spectrographe {gamma} avec elimination de l'effet Compton. (auteur)

  20. Par Pond vegetation status Summer 1995 -- Summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1996-01-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar to the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  1. A cluster of aspartic residues in the extracellular loop II of PAR 4 is important for thrombin interaction and activation of platelets.

    Science.gov (United States)

    Sánchez Centellas, Daniel; Gudlur, Sushanth; Vicente-Carrillo, Alejandro; Ramström, Sofia; Lindahl, Tomas L

    2017-06-01

    Thrombin activates platelets via proteolytic cleavage of protease-activated receptors (PARs) 1 and 4. The two PARs have distinct but complementary roles. The mechanisms responsible for PAR1 activation by thrombin have been extensively studied. However, much less is known regarding thrombin activation of PAR4, especially the potential involvement of regions of PAR4 other than the N-terminal, which is bound to the catalytic site of thrombin. We have studied PAR4 in S. cerevisiae strain MMY12, an expression system in which the GPCR receptors are connected to a Lac Z reporter gene resulting in increased β-galactosidase activity. This approach was used to assess PAR4 mutants to evaluate the contribution of different aspartic residues in facilitating PAR4 activation. Furthermore, peptides mimicking parts of the PAR4 N-terminal and the second extracellular loop (ECLII) were tested for their ability to inhibit platelet activation by thrombin. Binding of these peptides to γ-thrombin was studied by monitoring the decrease in tryptophan fluorescence intensity of thrombin. We conclude that not only the N-terminal but also the electronegative aspartic residues D224, D230 and D235 (located in ECLII) are be important for PAR4 binding to thrombin. We further suggest that they play a role for the tethered ligand binding to the receptor, as mutations also affected activation in response to a PAR4-activating peptide mimicking the new N-terminal formed after cleavage. This agrees with previous results on PAR1 and thrombin binding. We suggest that the ECLII of PAR4 could be a potential target for antithrombotic drug development. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. ¡París!

    Directory of Open Access Journals (Sweden)

    Beatriz Caballero

    2003-01-01

    Full Text Available El día no le alcanzaba para caminarlo. Conocía cada puente, cada calle,plaza, museo, rincón, iglesia, café, y la mesa con el mejor ángulo para mirar siempre una iglesia, ojalá Saint-Germain-des-Pres, o Notre-Dame. Siempre contaba la impresión que le había causado a Bolívar ver allí cuando el papa coronó a Napoleón. Él se iba para la oficina todos los días, Luis a un taller a pintar, Antonio a estudiar ciencias políticas, yo al colegio y mamá hacía las cosas prácticas. Aprendíamos francés todos al tiempo y por la noche nos contábamos lo nuevo que cada uno había aprendido. Mamá después, cuando ya se quería volver, decía que París nos había maleado a todos. Estaba en pleno furor el cine francés de la "nueva ola", pero ella sólo me llevaba a ver películas de vaqueros pues no se fiaba de la clasificación de los periódicos.

  3. C9.A/14 steelwork joints de poutres par plaque frontale : assemblages par gousset

    CERN Document Server

    2015-01-01

    Les Tables de résistances ultimes des assemblages boulonnés par plaque frontale et par gousset, complétées par une description des modèles de calcul et des exemples d’application, ont pour but de faciliter la tâche de l'ingénieur et du constructeur. Cette première partie C9.A/14 contient les chapitres suivants: - Joints de poutres par plaque frontale en acier S235 et S355 - Assemblages par gousset en acier S235 et S355 Les Tables contiennent des données relatives à la géométrie ainsi que les valeurs de calcul correspondantes des résistances ultimes des assemblages ; elles remplacent le chapitre « Assemblages par plaques frontales et boulons HR » des anciennes Tables C9.1 de 1983 / 2002. Le calcul de ces assemblages par plaque frontale est basé sur les hypothèses du modèle de la méthode des composants décrite dans la norme SN EN 1993-1-8. Les vérifications sont effectuées selon la norme SIA 263:2013. Les assemblages par gousset remplacent les assemblages par double cornière, (telle...

  4. Measurements of fission cross-sections and of neutron production rates; Mesures de sections efficaces de fission et du nombre de neutrons prompts emis par fission

    Energy Technology Data Exchange (ETDEWEB)

    Billaud, P; Clair, C; Gaudin, M; Genin, R; Joly, R; Leroy, J L; Michaudon, A; Ouvry, J; Signarbieux, C; Vendryes, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    } sert de moniteur. b) Mesure de la section efficace de fission de l'uranium-235. Nous comptons effectuer sous peu une mesure de la variation de la section efficace de fission de l'uranium-235 pour des neutrons d'energie superieure a 5 eV et jusqu'a 1 keV, par la methode du temps de vol. La source de neutrons est la cible en uranium d'un accelerateur lineaire pulse d'electrons de 28 MeV. Le detecteur est une chambre a fission a plateaux paralleles de grande dimension contenant au total environ 10 g d'uranium-235 (20 depots de 25 cm de diametre). Les mesures de fission sont corrigees pour tenir compte de la forme du spectre des neutrons, mesure a l'aide d'un assemblage de compteurs a BF{sub 3}. c) Etude sur le nombre moyen de neutrons emis par fission. Nous avons mesure la valeur du nombre moyen {nu} de neutrons emis par fission, de divers isotopes fissiles, induite par des neutrons de 14 MeV. Les neutrons de 14 MeV sont produits par reaction D(t, n) {alpha} a l'aide d'un generateur Cockroft-Walton de 300 kV. (auteur)

  5. Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis

    NARCIS (Netherlands)

    Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

    2015-01-01

    Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced

  6. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  7. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  8. Reviews in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2010-01-01

    This volume serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence spectroscopy. It summarizes the year's progress in fluorescence and its applications as well as includes authoritative analytical reviews.

  9. Fluorescent optical position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  10. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I [Berkeley, CA; Fergenson, David P [Alamo, CA; Srivastava, Abneesh [Santa Clara, CA; Bogan, Michael J [Dublin, CA; Riot, Vincent J [Oakland, CA; Frank, Matthias [Oakland, CA

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  11. Optimization of fluorescent proteins

    NARCIS (Netherlands)

    Bindels, D.S.; Goedhart, J.; Hink, M.A.; van Weeren, L.; Joosen, L.; Gadella (jr.), T.W.J.; Engelborghs, Y.; Visser, A.J.W.G.

    2014-01-01

    Nowadays, fluorescent protein (FP) variants have been engineered to fluoresce in all different colors; to display photoswitchable, or photochromic, behavior; or to show yet other beneficial properties that enable or enhance a still growing set of new fluorescence spectroscopy and microcopy

  12. ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation

    Science.gov (United States)

    Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta

    2016-01-01

    In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces. To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

  13. Research on the Primary Processes of Radiation-Initiated Polymerization; Recherches sur les processus primaires de polymerisation amorcee par rayonnements; Issledovaniya osnovnykh protsessov polimerizatsii pod vozdejstviem oblucheniya; Estudios sobre los procesos primarios en la polimerizacion radioinducida

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, S; Manabe, T; Higashimura, T; Oishi, Y; Futami, S

    1960-07-15

    Excitation energy transfer in benzene solutions of monomers, polymers and copolymers has been studied by observations on the quenching of terphenyl fluorescence produced by gamma radiation. The ease of energy transfer from benzene to various monomers is conjugated monomers > unconjugated > monomers > corresponding saturated compounds. Quenching experiments were also carried out using polymer solutions in benzene. The order of efficiencies was crepe rubber > polystyrene > polyvinyl acetate > acrylic polymers. The results obtained for quenching by a styrene-methyl methacrylate copolymer indicated that the specific quenching efficiency of the styrene units in the copolymer was less than in the homopolymer. The gamma ray initiated polymerisation of styrene in methylene dichloride solutions at low temperature was studied. The results obtained for the dependence of polymerisation rate on intensity are consistent with an ionic mechanism. The composition of the copolymer obtained with methyl methacrylate also supports this view. (author) [French] Les auteurs ont etudie la transmission de l'energie d'excitation dans les solutions de benzene du fait de la presence de monomeres, polymeres et copolymeres, en etudiant l'extinction de la fluorescence du terphenyle induite par rayons gamma. On peut classer les divers monomeres en trois categories selon l'ordre de facilite avec laquelle l'energie du benzene leur est transmise : monomeres conjugues, monomeres non conjugues, composes satures correspondants. Les auteurs ont egalement fait des experiences sur des polymeres dans une solution de benzene. L'efficacite va en decroissant dans l'ordre suivant: caoutchouc naturel, polystyrolene, acetate de polyvinyle, polymere acrylique. Les resultats obtenus pour le copolymere styrolene-methacrylate de methyle montrent que l'efficacite d'extinction du styrolene est plus faible dans le cas des copolymeres que dans le cas des homopolymeres. Les auteurs ont etudie la polymerisation du

  14. Contamination potentielle des aliments par des ...

    African Journals Online (AJOL)

    SARA Computers

    la notion de la pollution et de l'exposition aux PCBs, lorsque 77% n'ont pas conscience de cette situation de risque ... 2018). Quoique la contamination par les. PCBs soit de faible niveau, elle est ...... Université Paris-Est, Paris, France ; 183.

  15. CFD analysis of PAR performance as function of inlet design

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kweonha, E-mail: khpark@kmou.ac.kr [Division of Mechanical and Energy systems Engineering, Korea Maritime University, Dongsam-dong, Yeongdo-gu, Busan 606-791 (Korea, Republic of); Khor, Chong Lee, E-mail: itachi_829@hotmail.com [Department of Mechanical Engineering, Korea Maritime University (Korea, Republic of)

    2016-01-15

    Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

  16. CFD analysis of PAR performance as function of inlet design

    International Nuclear Information System (INIS)

    Park, Kweonha; Khor, Chong Lee

    2016-01-01

    Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

  17. SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign (March,...

  18. Analysis methods of neutrons induced resonances in the transmission experiments by time-of-flight and automation of these methods on IBM 7094 II computer; Methode d'analyse des resonances induites par les neutrons dans les experiences de transmission par temps-de-vol et automatisation de ces methodes sur ordinateur IBM-7094 II

    Energy Technology Data Exchange (ETDEWEB)

    Corge, C

    1967-07-01

    The neutron induced resonances analysis aims to determine the neutrons characteristics, leading to the excitation energies, de-excitation probabilities by gamma radiation emission, by neutron emission or by fission, their spin, their parity... This document describes the methods developed, or adapted, the calculation schemes and the algorithms implemented to realize such analysis on a computer, from data obtained during time-of-flight experiments on the linear accelerator of Saclay. (A.L.B.)

  19. Analysis methods of neutrons induced resonances in the transmission experiments by time-of-flight and automation of these methods on IBM 7094 II computer; Methode d'analyse des resonances induites par les neutrons dans les experiences de transmission par temps-de-vol et automatisation de ces methodes sur ordinateur IBM-7094 II

    Energy Technology Data Exchange (ETDEWEB)

    Corge, C

    1967-07-01

    The neutron induced resonances analysis aims to determine the neutrons characteristics, leading to the excitation energies, de-excitation probabilities by gamma radiation emission, by neutron emission or by fission, their spin, their parity... This document describes the methods developed, or adapted, the calculation schemes and the algorithms implemented to realize such analysis on a computer, from data obtained during time-of-flight experiments on the linear accelerator of Saclay. (A.L.B.)

  20. Nuclear structure of weakly bound radioactive nuclei through elastic and and inelastic scattering on proton. Impacts of the couplings induced by these exotic nuclei on direct reactions; Structure de noyaux radioactifs faiblement lies par diffusions elastiques et inelastiques sur proton. Effets des couplages induits par ces noyaux exotiques sur les reactions directes

    Energy Technology Data Exchange (ETDEWEB)

    Lapoux, V

    2005-09-15

    Information on the structure, spectroscopy and target interaction potentials of exotic nuclei can be inferred by interpreting measured data from direct reactions on proton such as elastic or inelastic scattering of proton (p,p') or one-nucleon transfer reaction (p,d). A series of experimental results has been obtained at the GANIL facilities on the setting composed of the MUST telescope array used for the detection of light charged-particles and of CATS beam detectors. This setting aims at measuring reactions on light proton or deuteron targets through reverse kinematics. Particularly, results on C{sup 10}, C{sup 11} and on direct reactions with the He{sup 8} beam of Spiral are presented. The first chapter is dedicated to the description of the most important theories concerning the nucleus. The experimental tools used to probe the nucleus are reported in the second chapter. The third and fourth chapters present the framework that has allowed us to analyse results from (p,p') and (p,d) reactions on weakly bound exotic nuclei. The last chapter is dedicated to the description of future experimental programs. (A.C.)

  1. Properties of point defects either native or induced by irradiation in the 3C and 6H polytypes of silicon carbide determined by positron annihilation and EPR; Proprietes des defauts ponctuels natifs et induits par irradiation dans les polytypes 3C et 6H du carbure de silicium determinees par annihilation de positons et RPE

    Energy Technology Data Exchange (ETDEWEB)

    Kerbiriou, X

    2006-02-15

    Potential applications of silicon carbide (SiC) in micro-electronics have justified many studies on point defects, which play an important role in the electrical compensation. Moreover, this material has many assets to take part in the fissile materials confining in the gas cooled reactors of the future (4. generation). In this thesis, we have used Electronic Paramagnetic Resonance and Positron Annihilation Spectroscopy to study the properties of point defects (nature, size, charge state, migration and agglomeration during annealing), either native or induced by irradiation with various particles (H{sup +}, e{sup -}, carbon ions), in the 3C and 6H polytypes of SiC. The positron annihilation study of native defects in 6H-SiC has shown the presence of a strong concentration of non-vacancy traps of acceptor type, which are not present in the 3C-SiC crystals. The nature of the defects detected after irradiation with low energy electrons (190 keV) depends on the polytype. Indeed, while silicon Frenkel pairs and carbon mono-vacancies are detected in the 6H crystals, only carbon mono-vacancies are detected in the 3C crystals. We propose that these differences concerning the populations of detected point defects result from different values of the silicon displacement threshold energy for the two polytypes (approximately 20 eV for 6H and 25 V for 3C). In addition, the irradiations with 12 MeV protons and 132 MeV carbon ions have created silicon mono-vacancies as well as VSi-VC di-vacancies. Neither the particle (protons or ions carbon), nor the polytype (3C or 6H) influence the nature of the generated defects. Finally the study of the annealing of 6H-SiC monocrystals irradiated with 12 MeV protons have revealed several successive processes. The most original result is the agglomeration of the silicon mono-vacancies with the VSi-VC di-vacancies which leads to the formation of VSi-VC-VSi tri-vacancies. (author)

  2. Plasma suPAR is lowered by smoking cessation

    DEFF Research Database (Denmark)

    Eugen-Olsen, Jesper; Ladelund, Steen; Sørensen, Lars Tue

    2016-01-01

    BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is a stable inflammatory biomarker. In patients, suPAR is a marker of disease presence, severity and prognosis. In the general population, suPAR is predictive of disease development, such as diabetes and cardiovascular disease a...

  3. Copenhagen uPAR prostate cancer (CuPCa) database

    DEFF Research Database (Denmark)

    Lippert, Solvej; Berg, Kasper D; Høyer-Hansen, Gunilla

    2016-01-01

    AIM: Urokinase plasminogen activator receptor (uPAR) plays a central role during cancer invasion by facilitating pericellular proteolysis. We initiated the prospective 'Copenhagen uPAR Prostate Cancer' study to investigate the significance of uPAR levels in prostate cancer (PCa) patients. METHODS...

  4. The inflammatory marker suPAR after cardiac arrest

    DEFF Research Database (Denmark)

    Rundgren, Malin; Lyngbaek, Stig; Fisker, Helle

    2015-01-01

    . This pilot study aimed at investigating suPAR levels in relation to outcome after CA and mild induced hypothermia. METHODS: suPAR levels were measured at 6, 36, and 72 hours in patients treated with hypothermia after CA. suPAR levels were analyzed in relation to survival after 6 months. Receiver operating...

  5. [Ambroise Paré in French literature].

    Science.gov (United States)

    Dumaitre, P

    1995-01-01

    The 16th century by its passionate side has been the favourite one of authors of historical novels in which among the heroes of "cloak and dagger stories" appears sometime Ambroise Paré. Alexandre Dumas (the father) has shown him at the court of Charles IX in La Reine Margot (1845) where he does not however play a great role. On the contrary, Balzac in Le Martyr calviniste (1842) has given him a capital part close to the dying François II, whom he intended to trepanize but had to give up this idea as a consequence of the opposition of the queen-mother Catherine de Médicis. In the present century, Robert Merle in Paris ma bonne ville (Fortune de France, 3, 1980) shows Paré at the time of the Saint Barthélemy.

  6. Par Pond refill water quality sampling

    International Nuclear Information System (INIS)

    Koch, J.W. II; Martin, F.D.; Westbury, H.M.

    1996-08-01

    This study was designed to document anoxia and its cause in the event that the anoxia caused a fish kill. However, no fish kill was observed during this study, and dissolved oxygen and nutrient concentrations generally remained within the range expected for southeastern reservoirs. Par Pond water quality monitoring will continue during the second summer after refill as the aquatic macrophytes become reestablished and nutrients in the sediments are released to the water column

  7. Atomic-fluorescence spectrophotometry

    International Nuclear Information System (INIS)

    Bakhturova, N.F.; Yudelevich, I.G.

    1975-01-01

    Atomic-fluorescence spectrophotometry, a comparatively new method for the analysis of trace quantities, has developed rapidly in the past ten years. Theoretical and experimental studies by many workers have shown that atomic-fluorescence spectrophotometry (AFS) is capable of achieving a better limit than atomic absorption for a large number of elements. The present review examines briefly the principles of atomic-fluorescence spectrophotometry and the types of fluorescent transition. The excitation sources, flame and nonflame atomizers, used in AFS are described. The limits of detection achieved up to the present, using flame and nonflame methods of atomization are given

  8. Fluorescence of irradiated hydrocarbons

    International Nuclear Information System (INIS)

    Gulis, I.G.; Evdokimenko, V.M.; Lapkovskij, M.P.; Petrov, P.T.; Gulis, I.M.; Markevich, S.V.

    1977-01-01

    A visible fluorescence has been found out in γ-irradiated aqueous of carbohydrates. Two bands have been distinguished in fluorescence spectra of the irradiated solution of dextran: a short-wave band lambdasub(max)=140 nm (where lambda is a wave length) at lambdasub(β)=380 nm and a long-wave band with lambdasub(max)=540 nm at lambdasub(β)=430 nm. A similar form of the spectrum has been obtained for irradiated solutions of starch, amylopectin, lowmolecular glucose. It has been concluded that a macromolecule of polysaccharides includes fluorescent centres. A relation between fluorescence and α-oxiketon groups formed under irradiation has been pointed out

  9. Centromere pairing by a plasmid-encoded type I ParB protein

    DEFF Research Database (Denmark)

    Ringgaard, Simon; Löwe, Jan; Gerdes, Kenn

    2007-01-01

    The par2 locus of Escherichia coli plasmid pB171 encodes two trans-acting proteins, ParA and ParB, and two cis-acting sites, parC1 and parC2, to which ParB binds cooperatively. ParA is related to MinD and oscillates in helical structures and thereby positions ParB/parC-carrying plasmids regularly......, hence identifying the N terminus of ParB as a requirement for ParB-mediated centromere pairing. These observations suggest that centromere pairing is an important intermediate step in plasmid partitioning mediated by the common type I loci....

  10. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...

  11. Multimodal fluorescence imaging spectroscopy

    NARCIS (Netherlands)

    Stopel, Martijn H W; Blum, Christian; Subramaniam, Vinod; Engelborghs, Yves; Visser, Anthonie J.W.G.

    2014-01-01

    Multimodal fluorescence imaging is a versatile method that has a wide application range from biological studies to materials science. Typical observables in multimodal fluorescence imaging are intensity, lifetime, excitation, and emission spectra which are recorded at chosen locations at the sample.

  12. Childhood Pars Planitis; Clinical Features and Outcomes

    Directory of Open Access Journals (Sweden)

    Homayoon Nikkhah

    2011-01-01

    Full Text Available Purpose: To evaluate the demographic and clinical features of childhood pars planitis, and to determine the therapeutic and visual outcomes of the disease. Methods: Medical records of pediatric patients (less than 16 years of age at diagnosis with pars planitis and at least 6 months of follow-up who were referred to Labbafinejad Medical Center, Tehran, Iran over a 22 year period were reviewed. Results: Overall, 117 eyes of 61 patients including 51 (83.6% male subjects were included. Mean age at the time of diagnosis was 7.8΁3.2 (range, 3-16 years. Mean best corrected visual acuity (BCVA was 0.88΁0.76 logMAR at presentation which improved to 0.39΁0.51 logMAR at final visit (P<0.001. Endotheliitis was present in 23 (19.6% eyes and was significantly more prevalent in subjects younger than 9 years (P=0.025. Cataract formation (41.9% and cystoid macular edema (19.7% were the most prevalent complications. Univariate regression analysis showed that better baseline visual acuity (OR=0.38, 95%CI 0.21-0.70, P=0.002, age older than 5 years at disease onset (OR=0.36, 95%CI 0.14-0.9, P=0.029, absence of endotheliitis (OR=0.39, 95%CI 0.15-0.99, P=0.047 and female gender (OR=3.77, 95%CI 1.03-13.93, P=0.046 were significantly associated with final BCVA of 20/40 or better. Conclusion: Childhood pars planitis was much more common among male subjects. Endotheliitis may be a sign of inflammation spillover and is more prevalent in younger patients. Visual prognosis is favorable in most patients with appropriate treatment.

  13. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  14. Induction of the lambda bacteriophage synthesis in Escherichia coli K 12 by polonium alpha rays; Induction de la synthese du bacteriophage lambda chez Escherichia coli K 12 par les rayons alpha du polonium

    Energy Technology Data Exchange (ETDEWEB)

    Devoret, Raymond

    1958-06-15

    This research thesis reports the study of the inducing action of polonium alpha radiations in Escherichia Coli K 12 by using an external irradiation device. This work comprised the development of a method to spread bacteria in layer with a thickness less than 20 microns, and the measurement of the number of α particles falling on the irradiated surface. This measurement has been performed by using a nuclear emulsion and a simple photographic film. It appears that alpha radiations have an inducing action, and that at most 15 per cent of bacteria can be induced. The comparison of the induction curve with the survival curves of lysogen and sensitive stains shows that there is no abortive induction. Thus, it appears that this inducing action is not due to an indirect effect of the irradiated medium [French] Dans ce travail on a etudie l'action inductrice des rayons alphas du polonium chez Escherichia Coli K 12 par un diapoaitif d'irradiation externe. Son utilisation necessitait: - une methode d'etalement des bacteries en couche de moins de 20 microns d'epaisseur; - une mesure du nombre des particules alpha tombant sur la surface etendue irradiee. Les mesures ont ete faites a l'aide d'une emulsion nucleaire et d'un film photographique ordinaire. 1) Les rayons alphas ont une action inductrice. Au plus 15 pc des bacteries peuvent etre induites. 2) La oomparaison de la courbe d'induction et des courbes de survie des souches lysogene et sensible montre qu'il n'y a pas d'inductions abortives. 3) Cette action inductrice n'est pas due a un effet indirect du milieu irradie. (auteur)

  15. Fluorescent discharge lamp

    Science.gov (United States)

    Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

    1982-01-01

    A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

  16. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  17. ANALYSE QUANTITATIVE PAR FLUORESCENCE DE VITAMINE E DANS LES FORMULES PHARMACEUTIQUES

    Directory of Open Access Journals (Sweden)

    Alexandru Stoica

    2011-02-01

    Full Text Available Many applications of this technique are encountered in the determination of organic compounds or molecules of biological importance, such as thiamin, riboflavin, adrenalin, cholesterol, paraffins or certain medications and drugs. Fluorimetric determinations are sensitive and selective and could determine the concentrations up to 10-10 g•mL-1, which corresponds to a sensitivity of 100 - 1000 times higher than most methods based on molecular absorption.This paper has developed two methods for spectrofluorimetric determination of vitamin E in pharmaceutical formulations (soft gelatin capsules of vitamin E and serum.

  18. Accouchement par forceps: indications et pronostic materno-foetal ...

    African Journals Online (AJOL)

    L'accouchement par voie basse, peut être parfois compromis par des facteurs maternels, foetaux ou materno-foetaux nécessitant des moyens thérapeutiques comme le forceps pour achever l'accouchement par voie naturelle. Le forceps, une méthode qui n'est pas sans risque pour la mère et le nouveau-né. Nous avons ...

  19. Reviews in fluorescence 2007

    CERN Document Server

    Lakowicz, Joseph R; Geddes, Chris D

    2009-01-01

    This fourth volume in the Springer series summarizes the year's progress in fluorescence, with authoritative analytical reviews specialized enough for professional researchers, yet also appealing to a wider audience of scientists in related fields.

  20. Introduction to fluorescence

    CERN Document Server

    Jameson, David M

    2014-01-01

    "An essential contribution to educating scientists in the principles of fluorescence. It will also be an important addition to the libraries of practitioners applying the principles of molecular fluorescence."-Ken Jacobson, Kenan Distinguished Professor of Cell Biology and Physiology, University of North Carolina at Chapel Hill"An exquisite compendium of fluorescence and its applications in biochemistry enriched by a very exciting historical perspective. This book will become a standard text for graduate students and other scientists."-Drs. Zygmunt (Karol) Gryczynski and Ignacy Gryczynski, University of North Texas Health Science Center"… truly a masterwork, combining clarity, precision, and good humor. The reader, novice or expert, will be pleased with the text and will not stop reading. It is a formidable account of the fluorescence field, which has impacted the life sciences so considerably in the last 60 years."-Jerson L. Silva, M.D., Ph.D., Professor and Director, National Institute of Science and Tech...

  1. Fluorescence (Multiwave) Confocal Microscopy.

    Science.gov (United States)

    Welzel, J; Kästle, Raphaela; Sattler, Elke C

    2016-10-01

    In addition to reflectance confocal microscopy, multiwave confocal microscopes with different laser wavelengths in combination with exogenous fluorophores allow fluorescence mode confocal microscopy in vivo and ex vivo. Fluorescence mode confocal microscopy improves the contrast between the epithelium and the surrounding soft tissue and allows the depiction of certain structures, like epithelial tumors, nerves, and glands. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Fluorescence Image Segmentation by using Digitally Reconstructed Fluorescence Images

    OpenAIRE

    Blumer, Clemens; Vivien, Cyprien; Oertner, Thomas G; Vetter, Thomas

    2011-01-01

    In biological experiments fluorescence imaging is used to image living and stimulated neurons. But the analysis of fluorescence images is a difficult task. It is not possible to conclude the shape of an object from fluorescence images alone. Therefore, it is not feasible to get good manual segmented nor ground truth data from fluorescence images. Supervised learning approaches are not possible without training data. To overcome this issues we propose to synthesize fluorescence images and call...

  3. In vivo measurements of the seasonal photosynthetic fluorescence of the Mediterranean coral Cladocora caespitosa (L.

    Directory of Open Access Journals (Sweden)

    Andrea Peirano

    2007-12-01

    Full Text Available In situ photosynthetic fluorescence of the zooxanthellate Mediterranean coral Cladocora caespitosa (L. was measured seasonally on colonies from 5 to 27 m depth using an INF-300 Integrating Natural Fluorometer (Biospherical Instrument Inc.. This oceanographic instrument, used to measure the in vivo phytoplankton chlorophyll a (Chl a fluorescence, was adapted to record the natural fluorescence of C. caespitosa by SCUBA divers. The resulting curves of natural fluorescence of Chl a vs photosynthetically active radiation (PAR 400-700 nm showed that: (1 natural fluorescence was limited by light availability in both deep and shallow colonies in all seasons; (2 photosynthesis occurred in C. caespitosa also in winter, when temperature is low and seawater turbidity contributes significantly to PAR attenuation; and (3 the efficiency of the Chl a fluorescence increased from summer to winter. This last finding outlines the winter coupling between zooxanthellae activity and calcification processes and is consistent with the formation of the high density band in the coral skeleton.

  4. PAR1 activation affects the neurotrophic properties of Schwann cells.

    Science.gov (United States)

    Pompili, Elena; Fabrizi, Cinzia; Somma, Francesca; Correani, Virginia; Maras, Bruno; Schininà, Maria Eugenia; Ciraci, Viviana; Artico, Marco; Fornai, Francesco; Fumagalli, Lorenzo

    2017-03-01

    Protease-activated receptor-1 (PAR1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR1 mRNA increased in response to sciatic nerve transection. In the sciatic nerve, functional PAR1 receptor was reported at the level of non-compacted Schwann cell myelin microvilli of the nodes of Ranvier. Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination. The present study was undertaken in order to determine if the activation of PAR1 affects the neurotrophic properties of Schwann cells. Our results suggest that the stimulation of PAR1 could potentiate the Schwann cell ability to favour nerve regeneration. In fact, the conditioned medium obtained from Schwann cell cultures challenged with a specific PAR1 activating peptide (PAR1 AP) displays increased neuroprotective and neurotrophic properties with respect to the culture medium from untreated Schwann cells. The proteomic analysis of secreted proteins in untreated and PAR1 AP-treated Schwann cells allowed the identification of factors differentially expressed in the two samples. Some of them (such as macrophage migration inhibitory factor, matrix metalloproteinase-2, decorin, syndecan 4, complement C1r subcomponent, angiogenic factor with G patch and FHA domains 1) appear to be transcriptionally regulated after PAR1 AP treatment as shown by RT-PCR. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Taare Zameen Par and dyslexic savants.

    Science.gov (United States)

    Chakravarty, Ambar

    2009-04-01

    The film Taare Zameen Par (Stars upon the Ground) portrays the tormented life at school and at home of a child with dyslexia and his eventual success after his artistic talents are discovered by his art teacher at the boarding school. The film hints at a curious neurocognitive phenomenon of creativity in the midst of language disability, as exemplified in the lives of people like Leonardo da Vinci and Albert Einstein, both of whom demonstrated extraordinary creativity even though they were probably affected with developmental learning disorders. It has been hypothesized that a developmental delay in the dominant hemisphere most likely 'disinhibits' the nondominant parietal lobe, unmasking talents-artistic or otherwise-in some such individuals. It has been suggested that, in remedial training, children with learning disorders be encouraged to develop such hidden talents to full capacity, rather than be subjected to the usual overemphasis on the correction of the disturbed coded symbol operations.

  6. Soudage de bois feuillus par friction rotationnelle

    OpenAIRE

    Belleville, Benoît

    2012-01-01

    Les différentes colles utilisées actuellement par l’industrie du meuble au Canada nécessitent des temps de polymérisation constituant un goulot dans la production des meubles et limitant l’atteinte de la production unitaire. Ces adhésifs synthétiques généralement issus de la pétrochimie nécessitent énormément d’énergie lors de leur confection. L’utilisation de connecteurs métalliques ou plastiques, quant à elle, limite les phases de découpage et sablage subséquentes. La présence d’adhésifs et...

  7. TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

    Science.gov (United States)

    Naeser, Margaret A.; Martin, Paula I.; Theoret, Hugo; Kobayashi, Masahito; Fregni, Felipe; Nicholas, Marjorie; Tormos, Jose M.; Steven, Megan S.; Baker, Errol H.; Pascual-Leone, Alvaro

    2011-01-01

    This study sought to discover if an optimum 1 cm2 area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1 Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions. PMID:21864891

  8. ParABS system in chromosome partitioning in the bacterium Myxococcus xanthus.

    Directory of Open Access Journals (Sweden)

    Antonio A Iniesta

    Full Text Available Chromosome segregation is an essential cellular function in eukaryotic and prokaryotic cells. The ParABS system is a fundamental player for a mitosis-like process in chromosome partitioning in many bacterial species. This work shows that the social bacterium Myxococcus xanthus also uses the ParABS system for chromosome segregation. Its large prokaryotic genome of 9.1 Mb contains 22 parS sequences near the origin of replication, and it is shown here that M. xanthus ParB binds preferentially to a consensus parS sequence in vitro. ParB and ParA are essential for cell viability in M. xanthus as in Caulobacter crescentus, but unlike in many other bacteria. Absence of ParB results in anucleate cells, chromosome segregation defects and loss of viability. Analysis of ParA subcellular localization shows that it clusters at the poles in all cells, and in some, in the DNA-free cell division plane between two chromosomal DNA masses. This ParA localization pattern depends on ParB but not on FtsZ. ParB inhibits the nonspecific interaction of ParA with DNA, and ParA colocalizes with chromosomal DNA only when ParB is depleted. The subcellular localization of ParB suggests a single ParB-parS complex localized at the edge of the nucleoid, next to a polar ParA cluster, with a second ParB-parS complex migrating after the replication of parS takes place to the opposite nucleoid edge, next to the other polar ParA cluster.

  9. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  10. Concerning the dynamic instability of actin homolog ParM

    International Nuclear Information System (INIS)

    Popp, David; Yamamoto, Akihiro; Iwasa, Mitsusada; Narita, Akihiro; Maeda, Kayo; Maeda, Yuichiro

    2007-01-01

    Using in vitro TIRF- and electron-microscopy, we reinvestigated the dynamics of native ParM, a prokaryotic DNA segregation protein and actin homolog. In contrast to a previous study, which used a cysteine ParM mutant, we find that the polymerization process of wild type ATP-ParM filaments consists of a polymerization phase and a subsequent steady state phase, which is dynamically unstable, like that of microtubules. We find that the apparent bidirectional polymerization of ParM, is not due to the intrinsic nature of this filament, but results from ParM forming randomly oriented bundles in the presence of crowding agents. Our results imply, that in the bacterium, ParM filaments spontaneously form bipolar bundles. Due to their intrinsic dynamic instability, ParM bundles can efficiently 'search' the cytoplasmic lumen for DNA, bind it equally well at the bipolar ends and segregate it approximately symmetrically, by the insertion of ParM subunits at either end

  11. The protein kinase SIK downregulates the polarity protein Par3

    DEFF Research Database (Denmark)

    Vanlandewijck, Michael; Dadras, Mahsa Shahidi; Lomnytska, Marta

    2018-01-01

    on Par3. Functionally, this mechanism impacts on tight junction downregulation. Furthermore, SIK contributes to the loss of epithelial polarity and examination of advanced and invasive human cancers of diverse origin displayed high levels of SIK expression and a corresponding low expression of Par3...

  12. Testing UK blood donors for exposure to human parvovirus 4 using a time-resolved fluorescence immunoassay to screen sera and Western blot to confirm reactive samples.

    Science.gov (United States)

    Maple, Peter A C; Beard, Stuart; Parry, Ruth P; Brown, Kevin E

    2013-10-01

    Human parvovirus 4 (ParV4), a newly described member of the family Parvoviridae, like B19V, has been found in pooled plasma preparations. The extent, and significance, of ParV4 exposure in UK blood donors remain to be determined and reliable detection of ParV4 immunoglobulin (Ig)G, using validated methods, is needed. With ParV4 virus-like particles a ParV4 IgG time-resolved fluorescence immunoassay (TRFIA) was developed. There is no gold standard or reference assay for measuring ParV4 IgG and the utility of the TRFIA was first examined using a panel of sera from people who inject drugs (PWIDS)--a high-prevalence population for ParV4 infection. Western blotting was used to confirm the specificity of TRFIA-reactive sera. Two cohorts of UK blood donor sera comprising 452 sera collected in 1999 and 156 sera collected in 2009 were tested for ParV4 IgG. Additional testing for B19V IgG, hepatitis C virus antibodies (anti-HCV), and ParV4 DNA was also undertaken. The rate of ParV4 IgG seroprevalence in PWIDS was 20.7% and ParV4 IgG was positively associated with the presence of anti-HCV with 68.4% ParV4 IgG-positive sera testing anti-HCV-positive versus 17.1% ParV4 IgG-negative sera. Overall seropositivity for ParV4 IgG, in 608 UK blood donors was 4.76%. The ParV4 IgG seropositivity for sera collected in 1999 was 5.08%, compared to 3.84% for sera collected in 2009. No ParV4 IgG-positive blood donor sera had detectable ParV4 DNA. ParV4 IgG has been found in UK blood donors and this finding needs further investigation. © 2013 American Association of Blood Banks.

  13. Recombination in the human Pseudoautosomal region PAR1.

    Directory of Open Access Journals (Sweden)

    Anjali G Hinch

    2014-07-01

    Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

  14. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs

  15. Fluorescence uranium determination

    International Nuclear Information System (INIS)

    Fernandez Cellini, R.; Crus Castillo, F. de la; Barrera Pinero, R.

    1960-01-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs

  16. Monitoring by fluorescence measurements

    International Nuclear Information System (INIS)

    Malcolme-Lawes, D.J.; Gifford, L.A.

    1981-01-01

    A fluorimetric detector is described in which the fluorescence excitation source may be 3 H, 14 C, 35 S, 147 Pm or 63 Ni. Such a detector can be adapted for use with flowing liquid systems especially liquid chromatography systems. (U.K.)

  17. Fluorescence lifetime based bioassays

    Science.gov (United States)

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  18. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    not be cited for purposes of advertisement. DISPOSITION INSTRUCTIONS: Destroy this document when no longer needed. Do not return to the... recycling , and can be disposed safely in a landfill. (2) LEDs offer reduced maintenance costs and fewer bulb replacements, significantly reducing... recycling . Several fixtures, ballasts and energy efficient fluorescent bulbs that were determined to be in pristine condition were returned to ATC

  19. PARs for combustible gas control in advanced light water reactors

    International Nuclear Information System (INIS)

    Hosler, J.; Sliter, G.

    1997-01-01

    This paper discusses the progress being made in the United States to introduce passive autocatalytic recombiner (PAR) technology as a cost-effective alternative to electric recombiners for controlling combustible gas produced in postulated accidents in both future Advanced Light Water Reactors (ALWRs) and certain U. S. operating nuclear plants. PARs catalytically recombine hydrogen and oxygen, gradually producing heat and water vapor. They have no moving parts and are self-starting and self-feeding, even under relatively cold and wet containment conditions. Buoyancy of the hot gases they create sets up natural convective flow that promotes mixing of combustible gases in a containment. In a non-inerted ALWR containment, two approaches each employing a combination of PARs and igniters are being considered to control hydrogen in design basis and severe accidents. In pre-inerted ALWRs, PARs alone control radiolytic oxygen produced in either accident type. The paper also discusses regulatory feedback regarding these combustible gas control approaches and describes a test program being conducted by the Electric Power Research Institute (EPRI) and Electricite de France (EdF) to supplement the existing PAR test database with performance data under conditions of interest to U.S. plants. Preliminary findings from the EPRI/EdF PAR model test program are included. Successful completion of this test program and confirmatory tests being sponsored by the U. S. NRC are expected to pave the way for use of PARs in ALWRs and operating plants. (author)

  20. Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Kapusta, Peter; Hof, Martin

    Roč. 406 , č. 20 (2014), s. 4797-4813 ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

  1. Determination of the physical values of a plasma puff by analysis of the diamagnetic signals. 1. part: expansion model for the puff. 2. part: comparison of experimental results with the expansion model for the plasma puff; Determination des grandeurs physiques d'une bouffee de plasma par l'analyse de signaux diamagnetiques. 1. partie: modele d'expansion de bouffee. 2. partie: confrontation des resultats experimentaux et du modele d'expansion de la bouffee de plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jacquinot, J; Leloup, Ch; Waelbroeck, F; Poffe, J P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The flow of a dense plasma puff, along the axis of a uniform magnetic field is examined, assuming the following hypotheses: the axial distribution of the line density can be described at any time by a gaussian function whose characteristic parameter is independent of the distance from the axis of the system; the {beta} ratio is less than 0,6. An approximate solution of the magnetohydrodynamics equations is obtained. The evolution of the characteristic properties of the plasma (local velocity, temperature and density) can be calculated from a set of equations involving 5 plasma parameters. A method leading to the determination of these parameters is described. It uses 5 informations picked up from the diamagnetic signals induced by the plasma into a set of 4 compensated magnetic loops. (authors) [French] L'ecoulement d'une bouffee dense de plasma le long des lignes de force d'un champ magnetique uniforme est etudie en faisant les hypotheses suivantes : la distribution axiale de la densite lineique est, a chaque instant, une gaussienne dont le parametre caracteristique ne depend pas de la distance a l'axe de revolution du systeme; {beta}(2 {mu}{sub 0} p/B{sup 2}{sub e}) est inferieur a 0,6. Dans ces conditions, une solution approchee des equations magneto-hydrodynamiques a pu etre trouvee. L'evolution des quantites physiques du plasma (vitesse, temperature, densite locale) est alors explicitement donnee par des equations dependant de 5 parametres. On decrit une methode permettant la determination de ces parametres. Elle necessite 5 informations prises sur les signaux diamagnetiques induits par le plasma dans un jeu de quatre boucles magnetiques compensees. (auteurs)

  2. Who's who in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2008-01-01

    The Journal of Fluorescence's sixth Who's Who directory publishes the names, contact details, specialty keywords, and a brief description of scientists employing fluorescence methodology and instrumentation in their working lives. This is a unique reference.

  3. uPAR as anti-cancer target

    DEFF Research Database (Denmark)

    Lund, Ida K; Illemann, Martin; Thurison, Tine

    2011-01-01

    , and a potential diagnostic and predictive impact of the different uPAR forms has been reported. Hence, pericellular proteolysis seems to be a suitable target for anti-cancer therapy and numerous approaches have been pursued. Targeting of this process may be achieved by preventing the binding of uPA to u...... using mouse monoclonal antibodies (mAbs) against mouse uPA or uPAR. These reagents will target uPA and uPAR in both stromal cells and cancer cells, and their therapeutic potential can now be assessed in syngenic mouse cancer models....

  4. Limnological database for Par Pond: 1959 to 1980

    International Nuclear Information System (INIS)

    Tilly, L.J.

    1981-03-01

    A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem

  5. Protease-activated receptor (PAR2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

    Directory of Open Access Journals (Sweden)

    Lisa G van den Hengel

    Full Text Available AIMS: In collateral development (i.e. arteriogenesis, mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. METHODS AND RESULTS: PAR1-deficient (PAR1-/-, PAR2-deficient (PAR2-/- and wild-type (WT mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low monocytes and the number of repair-associated (CD206-positive macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. CONCLUSION: PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD patients.

  6. Novel role for proteinase-activated receptor 2 (PAR2) in membrane trafficking of proteinase-activated receptor 4 (PAR4).

    Science.gov (United States)

    Cunningham, Margaret R; McIntosh, Kathryn A; Pediani, John D; Robben, Joris; Cooke, Alexandra E; Nilsson, Mary; Gould, Gwyn W; Mundell, Stuart; Milligan, Graeme; Plevin, Robin

    2012-05-11

    Proteinase-activated receptors 4 (PAR(4)) is a class A G protein-coupled receptor (GPCR) recognized through the ability of serine proteases such as thrombin and trypsin to mediate receptor activation. Due to the irreversible nature of activation, a fresh supply of receptor is required to be mobilized to the cell surface for responsiveness to agonist to be sustained. Unlike other PAR subtypes, the mechanisms regulating receptor trafficking of PAR(4) remain unknown. Here, we report novel features of the intracellular trafficking of PAR(4) to the plasma membrane. PAR(4) was poorly expressed at the plasma membrane and largely retained in the endoplasmic reticulum (ER) in a complex with the COPI protein subunit β-COP1. Analysis of the PAR(4) protein sequence identified an arginine-based (RXR) ER retention sequence located within intracellular loop-2 (R(183)AR → A(183)AA), mutation of which allowed efficient membrane delivery of PAR(4). Interestingly, co-expression with PAR(2) facilitated plasma membrane delivery of PAR(4), an effect produced through disruption of β-COP1 binding and facilitation of interaction with the chaperone protein 14-3-3ζ. Intermolecular FRET studies confirmed heterodimerization between PAR(2) and PAR(4). PAR(2) also enhanced glycosylation of PAR(4) and activation of PAR(4) signaling. Our results identify a novel regulatory role for PAR(2) in the anterograde traffic of PAR(4). PAR(2) was shown to both facilitate and abrogate protein interactions with PAR(4), impacting upon receptor localization and cell signal transduction. This work is likely to impact markedly upon the understanding of the receptor pharmacology of PAR(4) in normal physiology and disease.

  7. Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    PENG Xian-fu; LI Hong-qi

    2009-01-01

    Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

  8. Fluorescence spectroscopy of dental calculus

    International Nuclear Information System (INIS)

    Bakhmutov, D; Gonchukov, S; Sukhinina, A

    2010-01-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined

  9. Fluorescence spectroscopy of dental calculus

    Science.gov (United States)

    Bakhmutov, D.; Gonchukov, S.; Sukhinina, A.

    2010-05-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined.

  10. Fluorescence Imaging Reveals Surface Contamination

    Science.gov (United States)

    Schirato, Richard; Polichar, Raulf

    1992-01-01

    In technique to detect surface contamination, object inspected illuminated by ultraviolet light to make contaminants fluoresce; low-light-level video camera views fluorescence. Image-processing techniques quantify distribution of contaminants. If fluorescence of material expected to contaminate surface is not intense, tagged with low concentration of dye.

  11. Who's who in fluorescence 2005

    CERN Document Server

    Geddes, Chris D

    2006-01-01

    The Journal of Fluorescence's third Who's Who directory publishes the names, contact details, specialty keywords, photographs, and a brief description of scientists employing fluorescence methodology and instrumentation in their working livesThe directory provides company contact details with a brief list of fluorescence-related products.

  12. Positron Accumulator Ring (PAR) power supply

    International Nuclear Information System (INIS)

    Fathizadeh, M.

    1995-01-01

    The Positron Accumulator Ring (PAR) consists of 8 dipole magnets connected in series. These magnets are energized via one 12-pulse dc power supply. The power supply consists of four phase controlled half-wave wye group converters. Each of the two half-wave converters are connected through an interphase transformer to obtain a full-wave converter with 120 degrees conduction. The input voltage for these two half-wave converters are 180 degrees apart. The two full-wave converters are connected in parallel through a third interphase transformer. This type of connection of the converters not only provides the required output current, it also improves the input power factor of the power supply. The output of the wye group converters is filtered through a passive L-R-C filter to reduce the ripple content of the output current. At low current values of the power supply the current ripple is high, thus a large filter is needed, which adds to the cost of the power supply, however at high output current levels, the current ripple is less severe. The large size of the filter can be reduced by adding an anti-parallel rectifier diode(D1) to the output of the power supply. A freewheeling diode(D2) is connected before the choke to circulate the current once the power supply is turned off. In order to measure the current in the magnet a high precision, low drift, zero flux current transductor is used. This transductor senses the magnet current which provides a feedback signal to control the gating of the converter's thyristors. A true 14 bit Digital to Analog Converter (DAC) is programmed by the control computer for the required current value, providing a reference for the current regulator. Fast correction of the line transients is provided by a relatively fast voltage loop controlled by a high gain slow response current loop

  13. First-in-human uPAR PET

    DEFF Research Database (Denmark)

    Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene

    2015-01-01

    A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive...... for targeted molecular imaging with PET. The safety, pharmacokinetic, biodistribution profile and radiation dosimetry after a single intravenous dose of (64)Cu-DOTA-AE105 were assessed by serial PET and computed tomography (CT) in 4 prostate, 3 breast and 3 bladder cancer patients. Safety assessment...... of invasion, metastasis and indicates poor prognosis. uPAR PET imaging therefore holds promise to be a new and innovative method for improved cancer diagnosis, staging and individual risk stratification. The uPAR specific peptide AE105 was conjugated to the macrocyclic chelator DOTA and labeled with (64)Cu...

  14. Contribution de la tomographie par coherence optique au diagnostic ...

    African Journals Online (AJOL)

    Contribution de la tomographie par coherence optique au diagnostic de la neuropathie optique toxique. C.O.A. Abouki, S Alamou, C.R.A. Assavedo, L Odoulami-Yehouessi, I Sounouvou, S Hounnou-Tchabi ...

  15. Fluorescence fluctuation spectroscopy (FFS)

    CERN Document Server

    Tetin, Sergey

    2012-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial with quality chapters authored by leaders in the field. This volume covers fluorescence fluctuation spectroscopy and includes chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells. Continues the legacy of this premier serial with quality chapters authored by leaders in the field Covers fluorescence fluctuation spectroscopy Contains chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells.

  16. Fluorescent quantification of melanin.

    Science.gov (United States)

    Fernandes, Bruno; Matamá, Teresa; Guimarães, Diana; Gomes, Andreia; Cavaco-Paulo, Artur

    2016-11-01

    Melanin quantification is reportedly performed by absorption spectroscopy, commonly at 405 nm. Here, we propose the implementation of fluorescence spectroscopy for melanin assessment. In a typical in vitro assay to assess melanin production in response to an external stimulus, absorption spectroscopy clearly overvalues melanin content. This method is also incapable of distinguishing non-melanotic/amelanotic control cells from those that are actually capable of performing melanogenesis. Therefore, fluorescence spectroscopy is the best method for melanin quantification as it proved to be highly specific and accurate, detecting even small variations in the synthesis of melanin. This method can also be applied to the quantification of melanin in more complex biological matrices like zebrafish embryos and human hair. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

    Directory of Open Access Journals (Sweden)

    Flavien Pillet

    Full Text Available Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

  18. Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

    Science.gov (United States)

    Pillet, Flavien; Passot, Fanny Marie; Pasta, Franck; Anton Leberre, Véronique; Bouet, Jean-Yves

    2017-01-01

    Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi) mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

  19. Prise en charge des intoxications par envenimation chez les enfants ...

    African Journals Online (AJOL)

    Les signes cliniques étaient dominés par les douleurs (98%) suivies des hémorragies (73,80%) pour les morsures de serpent, la douleur pour les piqures de scorpion (100%) et les oedèmes pour les piqures d'abeilles (100%). Les cas de morsure de serpent ont été traités par le sérum antivenimeux polyvalent. Conclusion: ...

  20. Intoxication par la paraphényléne-diamine

    African Journals Online (AJOL)

    raoul

    9 mars 2011 ... remède contre la douleur par Averbukh [8], ou contre la constipation par Schemesh [9], mais l´utilisation à des fins autolytique reste toujours prédominante. Le tableau clinique de l´intoxication à ... une anurie ayant nécessité le recours à l´hémodialyse. Ce taux de survenue d´IRA anurique est relativement ...

  1. Croissance epitaxiale de GaAs sur substrats de Ge par epitaxie par faisceaux chimiques

    Science.gov (United States)

    Belanger, Simon

    La situation energetique et les enjeux environnementaux auxquels la societe est confrontee entrainent un interet grandissant pour la production d'electricite a partir de l'energie solaire. Parmi les technologies actuellement disponibles, la filiere du photovoltaique a concentrateur solaire (CPV pour concentrator photovoltaics) possede un rendement superieur et mi potentiel interessant a condition que ses couts de production soient competitifs. La methode d'epitaxie par faisceaux chimiques (CBE pour chemical beam epitaxy) possede plusieurs caracteristiques qui la rendent interessante pour la production a grande echelle de cellules photovoltaiques a jonctions multiples a base de semi-conducteurs III-V. Ce type de cellule possede la meilleure efficacite atteinte a ce jour et est utilise sur les satellites et les systemes photovoltaiques a concentrateur solaire (CPV) les plus efficaces. Une des principales forces de la technique CBE se trouve dans son potentiel d'efficacite d'utilisation des materiaux source qui est superieur a celui de la technique d'epitaxie qui est couramment utilisee pour la production a grande echelle de ces cellules. Ce memoire de maitrise presente les travaux effectues dans le but d'evaluer le potentiel de la technique CBE pour realiser la croissance de couches de GaAs sur des substrats de Ge. Cette croissance constitue la premiere etape de fabrication de nombreux modeles de cellules solaires a haute performance decrites plus haut. La realisation de ce projet a necessite le developpement d'un procede de preparation de surface pour les substrats de germanium, la realisation de nombreuses sceances de croissance epitaxiale et la caracterisation des materiaux obtenus par microscopie optique, microscopie a force atomique (AFM), diffraction des rayons-X a haute resolution (HRXRD), microscopie electronique a transmission (TEM), photoluminescence a basse temperature (LTPL) et spectrometrie de masse des ions secondaires (SIMS). Les experiences ont permis

  2. Fluorescent nanodiamond for biomedicine

    International Nuclear Information System (INIS)

    Milos Nesladek

    2014-01-01

    NV centers in diamond have gained strong interest as a novel tool for quantum information processing, quantum computing and quantum photonics. These applications are based on fluorescent and spin properties of NV-centres. However, in some conditions NV- can lose an electron and turn to NV0. The occupation of NV0 and NV- charge states depend on the position of their ground states with respect to the Fermi level and the mechanism of the charge transfer. Interestingly, that the charge switch has important implications on applications of fluorescent nanodiamond (fND) to nano-biology and nano-medicine. fND can be used for bio-marking and bio-tracking but also for the monitoring of targeted delivery to the cells. In this presentation we review the current state-of-the art for using fND particles for fluorescent bio imaging in cells and discuss the charge transfer and its luminescence stability by using ultra high sensitive spectroscopy methods to study the NV0 and NV- state occupation. (author)

  3. Serum suPAR in patients with FSGS: trash or treasure?

    NARCIS (Netherlands)

    Maas, R.J.H.; Deegens, J.K.J.; Wetzels, J.F.M.

    2013-01-01

    The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both

  4. Radiation retinopathy; Les retinopathies radio-induites

    Energy Technology Data Exchange (ETDEWEB)

    Lumbroso, L.; Desjardins, L. [Institut Curie, Serv. d' Ophtalmologie, 75 - Paris (France); Dendale, R.; Fourquet, A. [Institut Curie, Serv. de Radiotherapie, 75 - Paris (France)

    2002-09-01

    Radiation retinopathy is a retinal micro-angiopathy, observed after irradiation of the eye. It can rarely lead to neo-vascular glaucoma and enucleation due to pain. It is due to a progressive retinal capillary then vascular occlusion. Total irradiation dose, dose fraction, and surface of the irradiated retina seem to be strong predictive factors for radiation retinopathy. Patients who underwent an irradiation near the eye (skull base tumors, nasal and paranasal tumors, or brain tumors) should be followed by periodic ophthalmologic examination to detect and treat when necessary the non perfusion areas. (authors)

  5. Une terreur par l’image

    Directory of Open Access Journals (Sweden)

    Annie DULONG

    2011-09-01

    Full Text Available Si d’autres événements — Hiroshima, la découverte des camps de concentration, la chute du mur de Berlin — ont, au cours du XXe siècle, marqué suffisamment l’imaginaire pour trouver leur réponse dans des œuvres d’art, le 11 septembre 2001 pose la question de la fictionnalisation autrement : il ne s’agit plus tant de combler les manques de la représentation, liés à l’absence d’images ou au délai dans leur dévoilement, mais bien de composer avec l’omniprésence d’une représentation martelée à la télévision et sur Internet. Que cette représentation soit partielle, tronquée et qu’il lui manque la présence des corps, ces grands absents des photographies et des images tournées par les journalistes, ne change rien au fait que c’est avec le trop-plein que les artistes doivent maintenant négocier.Cet article s’intéresse aux romans qui traitent l’événement de front au lieu de l’aborder sur un mode mineur, et a pour objectif de tracer un portrait de la représentation des médias dans les romans du 11 septembre 2001. Ces romans, outre le fait qu’ils traitent des événements de New York, ont comme point commun un personnage, ou décor : les médias, représentés par la télévision, l’Internet, les photographies de presse, interviennent dans les récits d’une manière significative et témoignent de la force brute des images. À travers une étude de certains des mécanismes à l’œuvre dans The Writing on the Wall (Lynne Sharon Schwartz, Extremely Loud and Incredibly Close (Jonathan Safran Foer, Falling Man (Don DeLillo et A Disorder Peculiar to the Country (Ken Kalfus, il s’agira de proposer des réponses à ces quelques questions : quel rôle les médias jouent-ils, et comment participent-ils au récit ? Quelle pression les images exercent-elles sur les personnages ? Que révèlent les personnages enfants dans leur rapport aux médias ? Quelle critique, finalement, les romans

  6. Par Pond vegetation status Summer 1995 -- June survey descriptive summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1995-06-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the shoreline aquatic plant communities in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level, indicated that much of the original plant communities and the intermediate shoreline communities present on the exposed sediments have been lost. The extensive old-field and emergent marsh communities that were present on the exposed shoreline during the drawdown have been flooded and much of the pre-drawdown Par Pond aquatic plant communities have not had sufficient time for re-establishment. The shoreline does, however, have extensive beds of maidencane which extend from the shoreline margin to areas as deep as 2 and perhaps 3 meters. Scattered individual plants of lotus and watershield are common and may indicate likely directions of future wetland development in Par Pond. In addition, within isolated coves, which apparently received ground water seepage and/or stream surface flows during the period of the Par Pond draw down, extensive beds of waterlilies and spike rush are common. Invasion of willow and red maple occurred along the lake shoreline as well. Although not absent from this survey, evidence of the extensive redevelopment of the large cattail and eel grass beds was not observed in this first survey of Par Pond. Future surveys during the growing seasons of 1995, 1996, and 1997 along with the evaluation of satellite date to map the areal extent of the macrophyte beds of Par Pond are planned

  7. Fluorescent microthermographic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barton, D.L.

    1993-09-01

    In the early days of microelectronics, design rules and feature sizes were large enough that sub-micron spatial resolution was not needed. Infrared or IR thermal techniques were available that calculated the object`s temperature from infrared emission. There is a fundamental spatial resolution limitation dependent on the wavelengths of light being used in the image formation process. As the integrated circuit feature sizes began to shrink toward the one micron level, the limitations imposed on IR thermal systems became more pronounced. Something else was needed to overcome this limitation. Liquid crystals have been used with great success, but they lack the temperature measurement capabilities of other techniques. The fluorescent microthermographic imaging technique (FMI) was developed to meet this need. This technique offers better than 0.01{degrees}C temperature resolution and is diffraction limited to 0.3 {mu}m spatial resolution. While the temperature resolution is comparable to that available on IR systems, the spatial resolution is much better. The FMI technique provides better spatial resolution by using a temperature dependent fluorescent film that emits light at 612 nm instead of the 1.5 {mu}m to 12 {mu}m range used by IR techniques. This tutorial starts with a review of blackbody radiation physics, the process by which all heated objects emit radiation to their surroundings, in order to understand the sources of information that are available to characterize an object`s surface temperature. The processes used in infrared thermal imaging are then detailed to point out the limitations of the technique but also to contrast it with the FMI process. The FMI technique is then described in detail, starting with the fluorescent film physics and ending with a series of examples of past applications of FMI.

  8. A fluorescence scanning electron microscope

    International Nuclear Information System (INIS)

    Kanemaru, Takaaki; Hirata, Kazuho; Takasu, Shin-ichi; Isobe, Shin-ichiro; Mizuki, Keiji; Mataka, Shuntaro; Nakamura, Kei-ichiro

    2009-01-01

    Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM) and an electron microscope (EM). In the current study, a scanning electron microscope (SEM) (JEOL JXA8600 M) was combined with a fluorescence digital camera microscope unit and this hybrid instrument was named a fluorescence SEM (FL-SEM). In the labeling of FL-SEM samples, both Fluolid, which is an organic EL dye, and Alexa Fluor, were employed. We successfully demonstrated that the FL-SEM is a simple and practical tool for correlative fluorescence and electron microscopy.

  9. Par Pond vegetation status Summer 1995 -- September survey descriptive summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1995-09-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this mid-September survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maidencane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys during the late growing seasons of 1995, and throughout 1996 and 1997, along with the evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  10. Par Pond vegetation status Summer 1995 -- October survey descriptive summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1995-11-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this late October survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maiden cane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  11. Development of a fluorescent cryocooler

    International Nuclear Information System (INIS)

    Edwards, B.C.; Buchwald, M.I.; Epstein, R.I.; Gosnell, T.R.; Mungan, C.E.

    1995-01-01

    Recent work at Los Alamos National Laboratory has demonstrated the physical principles for a new type of solid-state cryocooler based on anti-Stokes fluorescence. Design studies indicate that a vibration-free, low-mass ''fluorescent cryocooler'' could operate for years with efficiencies and cooling powers comparable to current commercial systems. This paper presents concepts for a fluorescent cryocooler, design considerations and expected performance

  12. Fluorescence of ceramic color standards

    International Nuclear Information System (INIS)

    Koo, Annette; Clare, John F.; Nield, Kathryn M.; Deadman, Andrew; Usadi, Eric

    2010-01-01

    Fluorescence has been found in color standards available for use in calibration and verification of color measuring instruments. The fluorescence is excited at wavelengths below about 600 nm and emitted above 700 nm, within the response range of silicon photodiodes, but at the edge of the response of most photomultipliers and outside the range commonly scanned in commercial colorimeters. The degree of fluorescence on two of a set of 12 glossy ceramic tiles is enough to introduce significant error when those tiles have been calibrated in one mode of measurement and are used in another. We report the nature of the fluorescence and the implications for color measurement.

  13. [Ambroise Paré, his death and his historians].

    Science.gov (United States)

    Dumaître, P

    2001-01-01

    Ambroise Paré died December the 20th., 1590. What happened after his death and what are we knowing about his life? Never forgotten, though a lack of care, we were waiting till the XIXth. century to get recollection upon a subject sustained only by accounts of his travels. After Percy, a surgeon who tried to write Paré's biography through the "Biographie universelle ancienne et moderne, de Michaud (1822)" and some second rank authors, Malgaigne is the first who inside a printing of the "Oeuvres complétes de Paré (1840-41)" has a fine look upon the question, though his work is incomplete and allows many mistakes. Doctors Chéreau and Jal, an historian, analysing civil status records, gave new information enlarged by doctors Le Paulmier, Turner and the U.S. native Janet Doe.

  14. Keratometric alterations following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy.

    Science.gov (United States)

    Citirik, Mehmet; Batman, Cosar; Bicer, Tolga; Zilelioglu, Orhan

    2009-09-01

    To assess the alterations in keratometric astigmatism following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy. Sixteen consecutive patients were enrolled into the study. Conventional vitrectomy was applied to eight of the cases and 25-gauge transconjunctival sutureless vitrectomy was performed in eight patients. Keratometry was performed before and after the surgery. In the 25-gauge transconjunctival sutureless pars plana vitrectomy group, statistically significant changes were not observed in the corneal curvature in any post-operative follow-up measurement (p > 0.05); whereas in the conventional pars plana vitrectomy group, statistically significant changes were observed in the first postoperative day (p = 0.01) and first postoperative month (p = 0.03). We noted that these changes returned to baseline in three months (p = 0.26). Both 25-gauge transconjunctival sutureless and conventional pars plana vitrectomy are effective surgical modalities for selected diseases of the posterior segment. Surgical procedures are critical for the visual rehabilitation of the patients. The post-operative corneal astigmatism of the vitrectomised eyes can be accurately determined at least two months post-operatively.

  15. Cyclanthaceae no estado do Pará, Brasil Cyclanthaceae in Pará State, Brazil

    Directory of Open Access Journals (Sweden)

    Eduardo da Silva Leal

    2012-12-01

    Full Text Available Cyclanthaceae apresenta distribuição exclusiva na região neotropical sendo bem diversificada nas terras baixas das florestas pluviais tropicais, ocorrendo do sul do México até a Mata Atlântica do sul do Brasil. Consistem de ervas terrestres, epífitas, hemiepífitas ou lianas. O tratamento taxonômico de Cyclanthaceae no Pará foi baseado em coleções de herbário, trabalhos de campo e consulta a bibliografia referente à família. Foram registradas 11 espécies: Asplundia altiscandens E.S. Leal, A. fanshawei (Maguire Harling, A. glandulosa (Gleason Harling, A. heteranthera Harling, A. latifrons (Drude Harling, A. schizotepala Harling, A. xiphophylla Harling, Cyclanthus bipartitus Poit. ex A. Rich., Evodianthus funifer (Poit. Lindm., Ludovia lancifolia Brongn. e Thoracocarpus bissectus (Vell. Harling. São apresentadas chave de identificação, descrições e ilustrações das espécies, além de comentários sobre distribuição geográfica, hábitat e período de floração e frutificação.Cyclanthaceae is a family with a distribution exclusively in the Neotropics and is well diversified in lowland rainforests, occurring from southern Mexico to the Atlantic Forest of southern Brazil. The family consists of terrestrial herbs, epiphytes, hemiepiphytes and lianas. This taxonomic treatment of the Cyclanthaceae from the state of Pará was based on herbarium specimens, fieldwork, and the literature. Eleven species were recorded: Asplundia altiscandens E.S. Leal, A. fanshawei (Maguire Harling, A. glandulosa (Gleason Harling, A. heteranthera Harling, A. latifrons (Drude Harling, A. schizotepala Harling, A. xiphophylla Harling, Cyclanthus bipartitus Poit. ex A. Rich., Evodianthus funifer (Poit. Lindm., Ludovia lancifolia Brongn. and Thoracocarpus bissectus (Vell. Harling. An identification key, descriptions and illustrations of species are presented. Additional information on the geographic distribution, habitat, and flowering and

  16. Canning by the diffusion caused by a heated die; Gainage par diffusion par filiere chauffante

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In this process, the uranium fuel is clad with a zirconium can by passing the element through a die. The operation takes place at a temperature varying between 500 and 1000 deg. C. The heating is obtained by passing low voltage electric current through the can. This process differs from the co-extrusion process in that the uranium is not deformed. The uranium is therefore machined to the final dimensions before canning, it can also be hollow. Two types of processes can be adopted for the extrusion: a) Process in which the binding of the can to the uranium is obtained without diffusion (here the can is at high temperature - subsequently cooled - and the uranium is at a low temperature); b) Process in which uranium-zirconium diffusion is initiated. No matter which process is adopted the element is subsequently heat treated in an over at 800 deg. C in order to obtain the final diffusion. The quality of this diffusion is dependent on the initial state of the surfaces and on the degree of vacuum maintained during the operation. (author) [French] Dans ce procede, la gaine zirconium est plaquee sur le combustible uranium par passage dans une filiere. L'operation a lieu a chaud, a une temperature variant entre 500 et 1000 deg. C. Le chauffage est assure par passage d'un courant basse tension dans la gaine. A la difference du procede de cofilage, l'uranium ne subit pas de deformation durant l'operation. Il est donc prealablement usine aux cotes definitives et peut etre creux. Deux processus sont possibles pendant le passage dans la filiere: a) Obtention d'un frettage de la gaine sur l'uranium sans diffusion (avec une gaine a haute temperature et un tube d'uranium a basse temperature, eventuellement refroidi); b) Obtention d'un commencement de diffusion uranium-zirconium. Quelque soit le processus adopte, la cartouche est ensuite traitee dans un four a 800 deg. C pour obtenir la diffusion definitive. La qualite de celle-ci depend essentiellement des etats de surface initiaux

  17. La projection par plasma : une revue

    Science.gov (United States)

    Fauchais, P.; Grimaud, A.; Vardelle, A.; Vardelle, M.

    are presented in the fields of aeronautics and mechanics. La qualité d'un dépôt projete par plasma dépend de nombreux paramètres que l'on commence à mieux appréhender du fait des progrès de la modélisation et de la métrologie tant des écoulements plasmas que des transferts plasma-particules ou que des conditions d'écrasement et de refroidissement des particules lors de leur impact sur le substrat ou les couches déjà déposées. Les techniques de mesure utilisdes et leurs limitations sont d'abord rappelées tant pour les jets de plasma que pour les particules en vol et l'importance des différents phénomènes intervenant dans les transferts plasma-particules est soulignée : gradients de température et de concentration d'espèces chimiques très élevés autour des particules, effets de propagation de la chaleur, notamment pour les particules céramiques, effet d'évaporation, effet de raréfaction sensible dès la pression atmosphérique. Les problèmes de distribution de taille et de vitesse d'injection des particules sont également abordés car ils conditionnent les distributions de trajectoires et donc le traitement des particules dans le jet de plasma. La génération du plasma montre d'une part 1'influence considérable de l'injection du gaz, de sa nature, du dessin de la chambre d'arc et de la tuyère ainsi que du pompage de l'air ambiant sur la longueur des jets de plasma d'arc et d'autre part les problèmes d'injection pour éviter le couplage avec la décharge dans les jets de plasmas R.E Tout ceci est illustré avec des exemples de dépôt d'alumine, de zircone, de cermet carbure et de nickel. L'écrasement des particules est ensuite abordé avec les problèmes de réactions chimiques, de trempe ultra-rapide et donc de structure cristalline des dépôts, d'adhdsion mais aussi de containtes résiduelles et de leur contrôle via les gradients de température dans les dépôts pendant le tir. Enfin quelques applications actuelles sont pr

  18. In vitro modulation of radiation-induced FAS-related apoptosis in CD34{sup +} progenitor cells by combination cytokines; Reduction de l'apoptose radio-induite impliquant le recepteur FAS au niveau des cellules hematopoietiques CD34{sup +} par une combinaison de cytokines

    Energy Technology Data Exchange (ETDEWEB)

    Drouet, M.; Mathieu, J.; Grenier, N.; Soutif, A.; Herodin, F

    1998-07-01

    Combination cytokines such as SCF, Flt-3 ligand, IL-3 and thrombopoietin can modulate Fas mRNA expression by in vitro irradiated CD34{sup +} cells which results in a moderate decrease of apoptotic ratio and an improved rate of clonogenicity of the irradiated progenitors. (authors)

  19. Dérégulations épigénétiques induites par la protéine fusion BRD4-NUT et caractérisation de la proteine NUT au cours de la spermatogenèse et dans les cancers

    OpenAIRE

    Reynoird , Nicolas

    2010-01-01

    Nowadays, it is clear that cancer cannot be reduced only to genetic abberations, and that a new parameter has to be considered, epigenetic. During my thesis, I have characterized the fusion protein BRD4-NUT, which results of a t(15;19) translocation observed in NUT midline carcinoma (NMC), highly aggressive and lethal. BRD4 contains a double bromodomain to interact with acetylated chromatin, thus recruting different complexes on chromatin. NUT is a protein of unknown function, specifically ex...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrino, St

    2004-03-01

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

  1. Measurement of double differential cross sections for light charged particles production in neutron induced reaction at 62.7 MeV on lead target; Mesures des sections efficaces doublement differentielles de production de particules chargees legeres lors de reactions induites par neutrons de 62.7 MeV sur cible de plomb

    Energy Technology Data Exchange (ETDEWEB)

    Kerveno, M

    2000-09-27

    In order to develop new options for nuclear waste management, studies are carrying out on the perfecting of hybrid systems (sub-critical reactor driven by accelerator). This thesis work takes place more precisely in the framework of nuclear data linked to hybrid systems development. Increasing the upper limit energy value (from 20 to 150 MeV) of data bases supposes that theoretical codes could have sufficient predictive power in this energy range. Thus it's necessary to measure new cross sections to constrain these codes. The experiment, performed at Louvain-la-Neuve Cyclotron, aims to determine the double differential cross sections for light charged particles production in neutron induced reactions at 62.7 MeV on natural lead target. The detection device consists of 6 NE102-CsI telescopes. Time of flight measurements are used to reconstruct the neutron energy spectra. The general framework (hybrid systems and associated nuclear data problematic) in which this work takes place is presented in a first part. The experimental set up used for our measurements is described in a second part. The three following parts are dedicated to the data analysis and double differential cross sections extraction. The particle discrimination, the energy calibration of detectors as the different corrections applied to the experimental spectra are related in details. And finally a comparative study between our experimental results and some theoretical predictions is presented. (author)

  2. Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect; Etude de la pulverisation du dioxyde d'uranium induite par des ions lourds multicharges de basse et tres basse energie cinetique; effet de la charge du projectile

    Energy Technology Data Exchange (ETDEWEB)

    Haranger, F

    2003-12-01

    Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

  3. Mesures de taux de production d'éléments gazeux et volatiles lors de réactions induites par des protons de 1 et 1,4 GeV sur des cibles épaisses de plomb-bismuth liquides

    CERN Document Server

    Tall, Yoro

    2008-01-01

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6th Euratom Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target which one molten lead-bismuth concept is studied by the SUBATECH (physique SUBAtomique et des TECHnologies associées) laboratory in Nantes. The irradiation of molten lead-bismuth target with energetic proton beam generates volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-b...

  4. Towards precision measurements of parity violation in cesium: construction of a new experiment using an active detection method by induced emission; Vers des mesures precises de violation de la parite dans le cesium: construction d'une experience nouvelle utilisant une detection active par emission induite

    Energy Technology Data Exchange (ETDEWEB)

    Jacquier, Ph

    1991-04-15

    Experiments that show the breaking of parity invariance in atoms can be considered as valid tests of the electroweak theory complementary to those made at high energies. The accurate measurement of the weak charge of a cesium nucleus would bring useful information on radiative corrections. The experiment, that is proposed in this work concerns the strongly forbidden 6S-7S transition of cesium at 540 nm, aims at reaching an accuracy of 1% for this measurement. Cesium atoms are first excited from 6S level to 7S level by a pulsed laser (10 ns) in the presence of a longitudinal electrical field. Then they are detected through induced emission by a probe laser set on 7S-6P(3/2) transition at 1.470 {mu}m. The transitory amplification of the probe beam can be over 100%.The vapour presents a strong plane dichroism due to the alignment of 7S level through the linear polarization of the pumping beam. The weak interaction in the atom makes this alignment tilt by a small angle (1 to 10 micro-radians) that the measurement of the polarization of the amplified probe enables us to determine. In this work we have described the 3 steps we have passed through: the test with a transverse field and a continuous laser beam, the use of a pulsed laser, and the setting of a longitudinal configuration. Preliminary results show that the experiment will be useful and feasible.

  5. One-nucleon transfer reactions induced by secondary beam of {sup 11}Be: study of the nuclear structure of the exotic nuclei {sup 11}Be and {sup 10}Li; Reactions de transfert d'un nucleon induites par un faisceau secondaire de {sup 11}Be: etude de la structure des noyaux exotiques {sup 11}Be et {sup 10}Li

    Energy Technology Data Exchange (ETDEWEB)

    Pita, S

    2000-09-01

    The structure of the neutron rich light nuclei {sup 11}Be and {sup 10}Li has been investigated by means of one nucleon transfer reactions. The experiments have been carried out at GANIL in inverse kinematics using {sup 11}Be secondary beams. The {sup 11}Be(p,d){sup 10}Be reaction bas been studied at 35.3 MeV/u. The {sup 10}Be ejectiles were analyzed by the spectrometer SPEG, and coincident deuterons were detected in the position sensitive silicon detector CHARISSA. Transfer cross sections to 0{sup +}{sub 1} and 2{sup +}{sub 1}, states in {sup 10}Be were measured up to {theta}{sub CM} = 16 deg. and compared to DWBA and CRC predictions. The effects of neutron-cure couplings on reaction form factors have been studied by solving coupled equations in the framework of a vibrational model. It is shown that the rate of core excitation {sup 10}Be{sub 2+} in the {sup 11}Be{sub gs} wave function is overestimated by a standard analysis with form factors given by the usual Separation Energy prescription. The former model predicts a rate of core excitation of 16% and leads to theoretical cross sections which are in good agreement with the experimental data. The aim of the {sup 11}Be(d,{sup 3}He){sup 10}Li experiment, realized at 37 MeV/u, was to measure the distribution of the 2s neutron strength in the unbound nucleus {sup 10}Li. The energy spectrum was deduced from the {sup 3}He energy and angle measured by the silicon strip detector array MUST. An asymmetric peak is clearly observed near the threshold, with a maximum at -S{sub n} = 130 keV. This constitutes a direct proof of the inversion of 2s and 1p{sub 1/2} shells in {sup 10}Li, which was until now a controversial question in spite of many experimental efforts. On the other band the analysis of the {sup 11}Be(d,t){sup 10}Be reaction studied in the same experiment confirms the results obtained in the {sup 11}Be(p,d){sup 10}Be reaction concerning the {sup 11}Be{sub gs} structure. This work shows the interest and feasibility of studies of the shell properties of exotic nuclei using transfer reactions induced by radioactive beams and constitutes the beginning of a program devoted to this kind of experiment. (author)

  6. Cooperative photo-induced effects: from photo-magnetism under continuous irradiation to ultra-fast phenomena - study through optical spectroscopy and X-ray diffraction; Effets photo-induits cooperatifs: du photomagnetisme sous irradiation continue aux phenomenes ultrarapides - etude par spectroscopie optique et diffraction X

    Energy Technology Data Exchange (ETDEWEB)

    Glijer, D

    2006-12-15

    The control with ultra-short laser pulses of the collective and concerted transformation of molecules driving a macroscopic state switching on an ultra-fast time scale in solid state opens new prospects in materials science. The goal is to realize at the material level what happens at the molecular level in femto-chemistry. These processes are highly cooperative and highly non-linear, leading to self-amplification and self-organization within the material, a so-called photo-induced phase transition with a new long range order (structural, magnetic, ferroelectric,...). Two families of molecular compounds have been studied here: first of all, spin transition materials changing from a diamagnetic state over to a paramagnetic state under the effect of temperature or under continuous laser excitation. It concerns photo-active molecular bi-stability prototype materials in solid state, whose switching has been studied during X-ray diffraction, optical reflectivity and magnetism experiments. Then we have studied charge-transfer molecular systems, prototype compounds for ultrafast photo-induced phase transitions: insulator-metal, neutral-ionic....As well as ultrafast optical experiments, time-resolved X ray crystallography is a key technique in order to follow at the atomic level the different steps of the photo-induced transformation and thus to observe the involved mechanisms. We have underlined a process of photo-formation of one-dimensional nano-domains of lattice-relaxed charge-transfer excitations, governing the photo-induced phase transition of the molecular charge-transfer complex TTF-CA by the first time-resolved diffuse scattering measurements. Moreover, a new femtosecond laser-plasma source and a optical pump-probe spectroscopy set-up with a highly sensitive detecting system have been developed in this work. The results presented here will be an illustration of the present scientific challenges existing on the one hand with the development of projects of major scale (new ultrafast sources) and on the other hand with ultrafast photo-switching. (author)

  7. Towards precision measurements of parity violation in cesium: construction of a new experiment using an active detection method by induced emission; Vers des mesures precises de violation de la parite dans le cesium: construction d'une experience nouvelle utilisant une detection active par emission induite

    Energy Technology Data Exchange (ETDEWEB)

    Jacquier, Ph

    1991-04-15

    Experiments that show the breaking of parity invariance in atoms can be considered as valid tests of the electroweak theory complementary to those made at high energies. The accurate measurement of the weak charge of a cesium nucleus would bring useful information on radiative corrections. The experiment, that is proposed in this work concerns the strongly forbidden 6S-7S transition of cesium at 540 nm, aims at reaching an accuracy of 1% for this measurement. Cesium atoms are first excited from 6S level to 7S level by a pulsed laser (10 ns) in the presence of a longitudinal electrical field. Then they are detected through induced emission by a probe laser set on 7S-6P(3/2) transition at 1.470 {mu}m. The transitory amplification of the probe beam can be over 100%.The vapour presents a strong plane dichroism due to the alignment of 7S level through the linear polarization of the pumping beam. The weak interaction in the atom makes this alignment tilt by a small angle (1 to 10 micro-radians) that the measurement of the polarization of the amplified probe enables us to determine. In this work we have described the 3 steps we have passed through: the test with a transverse field and a continuous laser beam, the use of a pulsed laser, and the setting of a longitudinal configuration. Preliminary results show that the experiment will be useful and feasible.

  8. Intergranular brittle fracture of a low alloy steel induced by grain boundary segregation of impurities: influence of the microstructure; Rupture intergranulaire fragile d'un acier faiblement allie induite par la segregation d'impuretes aux joints de grains: influence de la microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Raoul, St

    1999-07-01

    The study contributes to improve the comprehension of intergranular embrittlement induced by the phosphorus segregation along prior austenitic grain boundaries of low alloy steels used in pressurized power reactor vessel. A part of this study was performed using a A533 steel which contains chemical fluctuations (ghost lines) with two intensities. Axi-symmetrically notched specimens were tested and intergranular brittle de-cohesions were observed in the ghost lines. The fracture initiation sites observed on fracture surfaces were identified as MnS inclusions. A bimodal statistic obtained in a probabilistic model of the fracture is explained by the double population of ghost lines' intensities. A metallurgical study was performed on the same class of steel by studying the influence of the microstructure on the susceptibility to temper embrittlement. Brittle fracture properties of such microstructures obtained by dilatometric experiments were tested on sub-sized specimens to measure the V-notched fracture toughness. Fraction areas of brittle fracture modes were determined on surface fractures. A transition of the fracture mode with the microstructure is observed. It is shown that tempered microstructures of martensite and lower bainite are more susceptible to intergranular embrittlement than tempered upper bainitic microstructure. The intergranular fracture is the most brittle mode. The analysis of crystalline mis-orientations shows a grain boundary structure appreciably more coherent for tempered microstructures of martensite and lower bainite. The higher density of randomgrain boundaries is susceptible to drag the phosphorus in the upper bainitic matrix and to make the quantity of free phosphorus decreasing. Microstructure observations show a difference in the size and the spatial distribution of carbides, essentially cementite, between tempered martensite and upper bainite. It can explain the bigger susceptibility of this last microstructure to cleavage mode. (author)

  9. Root uptake of uranium (6) in solution by a higher plant: speciation in hydroponic solution, bioavailability, micro-localisation and biological effects induced; Transfert racinaire de l'uranium (6) en solution chez une plante superieure: speciation en solution hydroponique, prise en charge par la plante, microlocalisation et effets biologiques induits

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, L

    2005-01-15

    Uranium exists naturally in the environment, usually present in trace quantities. In soil solution and oxic conditions, uranium is present in the +VI oxidation state and forms a large number of inorganic and organic complexes. The exposure medium, an artificial soil solution, was designed in such a way as to control the uranium species in solution. The geochemical speciation code JCHESS was used to calculate the uranium aqueous species concentration and to define the domains of interest, each of them characterized by a limited number of dominant U species. These domains were defined as follows: pH 4.9 with uranyl ions as dominant species, pH 5.8 with hydroxyl complexes and pH 7 where carbonates play a major role. For each pH, short-duration (5 hours of exposure) well-defined laboratory experiments were carried out with Phaseolus vulgaris as plant model. The effect of competitive ions such as Ca{sup 2+} or the presence of ligands such as phosphate or citrate on root assimilation efficiency was explored. Results have shown that uranium transfer was not affected by the presence of calcium, phosphate or citrate (but was decreased of 60% with citrate (10 {mu}M) at pH 5.8) in our experimental conditions. Moreover, observation in Transmission Electronic Microscopy (TEM), equipped with an EDAX probe, have shown that uranium was associated with granules rich in phosphorus and that there were some chloroplast anomalies. Finally, the presence of uranium affects root CEC by reducing it and stimulates root elongation at low uranium concentrations (100 nM, 400 nM and 2 {mu}M at pHs 4.9, 5.8 and 7 respectively) and inhibits it at high uranium concentrations. (author)

  10. Micro-seismicity induced by hydrocarbon production: contribution to localization of events and identification of the source mechanisms through the use of dynamic friction models; Contribution a la localisation des evenements et l'identification des mecanismes au foyer en micro-sismicite induite par l'exploitation d'hydrocarbures. Utilisation des modeles de frottement dynamique

    Energy Technology Data Exchange (ETDEWEB)

    Mohammedi, H.

    2002-11-01

    Oil production or any injection of fluid in a geological medium is likely to impose variations of stresses which might generate micro-seismicity. We examine whether the use of dynamic friction models could allow for a better determination of mechanics on the fault plane from borehole seismometers. We sought to identify the friction law model from seismogram observation. Before dealing with this inverse problem, we examined the direct problem generating synthetic seismograms at virtual stations, on the basis of a postulated friction law using the FD3D earthquake simulation code and the AXITRA radiation computation code. Treatment of two different laws, one of which is an original variation of the Dietrich-Ruina law, leads to similar seismograms. This might indicate that systematic inversion for the friction law only from seismogram observation might reveal difficult. (authors)

  11. Measurement of double differential cross sections for light charged particles production in neutron induced reaction at 62.7 MeV on lead target; Mesures des sections efficaces doublement differentielles de production de particules chargees legeres lors de reactions induites par neutrons de 62.7 MeV sur cible de plomb

    Energy Technology Data Exchange (ETDEWEB)

    Kerveno, M

    2000-09-27

    In order to develop new options for nuclear waste management, studies are carrying out on the perfecting of hybrid systems (sub-critical reactor driven by accelerator). This thesis work takes place more precisely in the framework of nuclear data linked to hybrid systems development. Increasing the upper limit energy value (from 20 to 150 MeV) of data bases supposes that theoretical codes could have sufficient predictive power in this energy range. Thus it's necessary to measure new cross sections to constrain these codes. The experiment, performed at Louvain-la-Neuve Cyclotron, aims to determine the double differential cross sections for light charged particles production in neutron induced reactions at 62.7 MeV on natural lead target. The detection device consists of 6 NE102-CsI telescopes. Time of flight measurements are used to reconstruct the neutron energy spectra. The general framework (hybrid systems and associated nuclear data problematic) in which this work takes place is presented in a first part. The experimental set up used for our measurements is described in a second part. The three following parts are dedicated to the data analysis and double differential cross sections extraction. The particle discrimination, the energy calibration of detectors as the different corrections applied to the experimental spectra are related in details. And finally a comparative study between our experimental results and some theoretical predictions is presented. (author)

  12. Measurement of cross-sections of fission reactions induced by neutrons on actinides from the thorium cycle at n-TOF facility; Mesures de sections efficaces de fission induite par neutrons sur des actinides du cycle du thorium a n-TOF

    Energy Technology Data Exchange (ETDEWEB)

    Ferrant, L

    2005-09-01

    In the frame of innovating energy source system studies, thorium fuel cycle reactors are considered. Neutron induced fission cross section on such cycle involved actinides play a role in scenario studies. To feed them, data bases are built with experimental results and nuclear models. For some nuclei, they are not complete or in disagreement. In order to complete these data bases, we have built an original set up, consisting in an alternation of PPACs (Parallel Plate Avalanche Chamber) and ultra - thin targets, which we installed on n-TOF facility. We describe detectors, set up, and the particular care brought to target making and characterization. Fission products in coincidence are detected with precise time measurement and localization with delay line read out method. We contributed, within the n-TOF collaboration, to the CERN brand new intense spallation neutron source characterization, based on time of flight measurement, and we describe its characteristics and performances. We were able to measure such actinide fission cross sections as {sup 232}Th, {sup 234}U, {sup 233}U, {sup 237}Np, {sup 209}Bi, and {sup nat}Pb relative to {sup 235}U et {sup 238}U standards, using an innovative acquisition system. We took advantage of the lame accessible energy field, from 0.7 eV to 1 GeV, combined with the excellent energy resolution in this field. Data treatment and analysis advancement are described to enlighten performance and limits of the obtained results. (author)

  13. Measurement of the fission cross section induced by fast neutrons of the {sup 232}Th/{sup 233}U nuclei within the innovating fuel cycles framework; Mesure de la section efficace de fission induite par neutrons rapides des noyaux {sup 232}Th/{sup 233}U dans le cadre des cycles de combustible innovants

    Energy Technology Data Exchange (ETDEWEB)

    Grosjean, C

    2005-03-15

    The thorium-U{sup 233} fuel cycle might provided safer and cleaner nuclear energy than the present Uranium/Pu fuelled reactors. Over the last 10 years, a vast campaign of measurements has been initiated to bring the precision of neutron data for the key nuclei (Th{sup 232}, Pa{sup 233} and U{sup 233}) at the level of those for the U-Pu cycle. This is the framework of these measurements, the energy dependent neutron induced fission cross section of Th{sup 232} and U{sup 233} has been measured from 1 to 7 MeV with a target accuracy lesser than 5 per cent. These measurements imply the accurate determination of the fission rate, the number of the target nuclei as well as the incident neutron flux impinging on the target, the latter has been obtained using the elastic scattering (n,p). The cross section of which is very well known in a large neutron energy domain ({approx} 0,5 % from 1 eV to 50 MeV) compared to the U{sup 235}(n,f) reaction. This technique has been applied for the first time to the Th{sup 232}(n,f) and U{sup 233}(n,f) cases. A Hauser-Feshbach statistical model has been developed. It consists of describing the different decay channels of the compound nucleus U{sup 234} from 0,01 to 10 MeV neutron energy. The parameters of this model were adjusted in order to reproduce the measured fission cross section of U{sup 233}. From these parameters, the cross sections from the following reactions could be extracted: inelastic scattering U{sup 233}(n,n'), radiative capture U{sup 233}(n,{gamma}) and U{sup 233}(n,2n). These cross sections are still difficult to measure by direct neutron reactions. The calculated values have allowed us to fill the lack of experimental data for the major fissile nucleus of the thorium cycle. (author)

  14. Fluorescing macerals from wood precursors

    Energy Technology Data Exchange (ETDEWEB)

    Stout, S A; Bensley, D F

    1987-01-01

    A preliminary investigation into the origin of wood-derived macerals has established the existence of autofluorescent maceral precursors in the secondary xylem of swamp-inhabiting plant species. The optical character and fluorescent properties of microtomed thin-sections of modern woods from the Florida Everglades and Okefenokee Swamp, Georgia are compared to the character and properties of their peatified equivalents from various Everglades and Okefenokee peat horizons and their lignitic equivalents from the Brandon lignite of Vermont and the Trail Ridge lignitic peat from northern Florida. The inherent fluorescence of woody cell walls is believed to be caused by lignin though other cell wall components may contribute. The fluorescence spectra for several wood and cell types had a ..gamma../sub m//sub a//sub x/ of 452 nm and Q value of 0.00. The color as observed in blue light and the spectral geometry as measured in UV light of peatified and lignitic woody cell walls (potential textinites) may change progressively during early coalification. Cell wall-derived maceral material is shown to maintain its fluorescing properties after being converted to a structureless material, perhaps a corpohuminite or humodetrinite precursor. Fluorescing xylem cell contents, such as condensed tannins or essential oils, can maintain the fluorescent character through early coalification. Xylem cell walls and xylem cell contents are shown to provide fluorescing progenitor materials which would not require subsequent infusion with 'lipid' materials to account for their fluorescence as phytoclast material or as macerals in coal. 35 references.

  15. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  16. Time-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gustavsson, Thomas; Mialocq, Jean-Claude

    2007-01-01

    This article addresses the evolution in time of light emitted by a molecular system after a brief photo-excitation. The authors first describe fluorescence from a photo-physical point of view and discuss the characterization of the excited state. Then, they explain some basic notions related to fluorescence characterization (lifetime and decays, quantum efficiency, so on). They present the different experimental methods and techniques currently used to study time-resolved fluorescence. They discuss basic notions of time resolution and spectral reconstruction. They briefly present some conventional methods: intensified Ccd cameras, photo-multipliers and photodiodes associated with a fast oscilloscope, and phase modulation. Other methods and techniques are more precisely presented: time-correlated single photon counting (principle, examples, and fluorescence lifetime imagery), streak camera (principle, examples), and optical methods like the Kerr optical effect (principle and examples) and fluorescence up-conversion (principle and theoretical considerations, examples of application)

  17. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    In prospects of global climate change, heat stress is a rising constraint for the productivity of wheat (Triticum aestivum L.). It is a heat-susceptible crop beyond 17-23oC temperature throughout its phenological stages, flowering phase being the most sensitive stage. Chlorophyll a fluorescence...... parameter, maximum quantum yield efficiency of PSII (Fv/Fm) is used as a physiological marker for early stress detection in PSII in plants. We established a reproducible protocol to measure response of wheat genotypes to high temperature based on Fv/Fm. The heat treatment of 40°C in 300 µmol m-2s-1 PAR...... enabled the identification of contrasting wheat genotypes that can be used to study the genetic and physiological nature of heat stress tolerance to dissect quantitative traits into simpler and more heritable traits....

  18. Single Molecule Spectroscopy of Fluorescent Proteins

    NARCIS (Netherlands)

    Blum, Christian; Subramaniam, Vinod

    2009-01-01

    The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject to intense research. Understanding the

  19. Fluorescent multiplex cell flow systems and methods

    KAUST Repository

    Merzaban, Jasmeen; Abuelela, Ayman F.; Mohammad, Amal Jehad

    2017-01-01

    scanning system emits multiple electromagnetic wavelengths simultaneously it cause multiple fluorescent labels having different excitation wavelength maximums to fluoresce. The system can simultaneously capture real-time fluorescence images from at least

  20. Parasitisme de Dacryodes edulis par le genre Tapinanthus ...

    African Journals Online (AJOL)

    SARAH

    31 août 2013 ... Parasitisme de Dacryodes edulis par le genre. Tapinanthus (Loranthaceae) et répartition de la myrmécofaune associée à Logbessou Plateau. (Douala, Cameroun). Massako F1*, Tchatat M2, Mony R3, Ladoh Yemeda CF1, Dibong SD1,4,5. 1Laboratoire de Biologie et Physiologie des Organismes ...

  1. Parasitisme des champs semenciers de cacaoyers par les ...

    African Journals Online (AJOL)

    SARAH

    30 janv. 2015 ... J. Appl. Biosci. Parasitisme des champs semenciers de cacaoyers par les loranthaceae dans la localité de Nkoemvone (sud Cameroun). 7795 to the various clones, Phragmanthera capitata was the most abundant Loranthaceae; the level of parasitism of cacao trees is more important at the cacao trees of ...

  2. Den eneste ene - hvordan etniske minoritetsunge i Danmark danner par

    DEFF Research Database (Denmark)

    Singla, Rashmi

    Rapporten handler om etniske unges måde at danne par på. Rapporten er baseret på en større empirisk undersøgelse gennemført af forfatteren i 2003 og er desuden inspireret af forfatterens egen ph.d.-afhandling: "Ungdom, etnicitet og psychosocial intervention" (2000, Københavns Universitet). Rappor...

  3. Indications and visual outcome of first hundred pars plana ...

    African Journals Online (AJOL)

    Objective: To review the indications and visual outcome of the first one hundred pars plana vitrectomies performed at the newly established surgical retina unit of Makkah Specialist Eye Hospital, Kano, Kano State, Nigeria. Materials and Methods: Aretrospective chart review was performed. Data recorded from the patient ...

  4. Epuration des effluents industriels par électroflottation Belkacem ...

    African Journals Online (AJOL)

    étudié la séparation de quelques métaux lourds tels que le fer, le nickel, ... the separation of some heavy metals such as iron, nickel, copper, zinc, lead and ... généralement basées sur l'adsorption (par ... Différents essais de concentration en.

  5. Predicting spectral and PAR light attenuation in Greenlandic coastal waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Markager, Stiig; Stedmon, Colin

    (CDOM), phytoplankton pigments and inorganic particles. These differences are due in part to hydrography and to the sources of meltwater: respectively, fjord-terminating and land-terminating glaciers. We present a model to explain the variation in spectral and PAR irradiance in terms of the variation...

  6. La lecture de Merleau-Ponty par Renaud Barbaras

    Czech Academy of Sciences Publication Activity Database

    Pechar, Jiří

    2015-01-01

    Roč. 11, č. 2 (2015), s. 1-6 ISSN 1336-6556 Institutional support: RVO:67985955 Keywords : Merleau-Ponty * Husserl * phenomenology * linguistics of Ferdinand de Saussure Subject RIV: AA - Philosophy ; Religion http://www.ostium.sk/sk/la-lecture-de-merleau-ponty-par-renaud-barbaras/

  7. Par Pond vegetation status summer 1995 - July survey descriptive summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1995-07-01

    A survey of the emergent shoreline aquatic plant, communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet (61 meters) above mean sea level, and continued with this July survey. Aquatic plant communities, similar to the pre-drawdown Par Pond communities, are becoming reestablished. Beds of maidencane (Panicum hemitomon), lotus (Nelumbo lutea), water lily (Nymphaea odorata), and watershield (Brasenia schreberi) are now extensive and well established. In addition, within isolated coves, extensive beds of water lilies and spike-rush (Eleocharis sp.) are common. Cattail occurrence has increased since refill, but large beds common to Par Pond prior to the drawdown have not formed. Invasion of willow (Salix sp.) and red maple (Acer rubrum) occurred along the lake shoreline during drawdown. The red maples along the present shoreline are beginning to show evidence of stress and mortality from flooding over the past four months. Some of the willows appear to be stressed as well. The loblolly pines (Pinus taeda), which were flooded in all but the shallow shoreline areas, are now dead. Future surveys are planned for the growing seasons of 1995, 1996, and 1997, along with the evaluation of satellite data for mapping the areal extent of the macrophyte beds of Par Pond

  8. fortification des farines tropicales par l'introduction de proteines ...

    African Journals Online (AJOL)

    2Université d'Abomey Calavy, Faculté des Sciences et Techniques, Bénin ... valeur recommandée par le Codex Alimentarius pour ce type de complément alimentaire destiné aux enfants. ..... neurotransmission, coagulation sanguine et.

  9. Fluorescent standards for photodynamic therapy

    Science.gov (United States)

    Belko, N.; Kavalenka, S.; Samtsov, M.

    2016-08-01

    Photodynamic therapy is an evolving technique for treatment of various oncological diseases. This method employs photosensitizers - species that lead to death of tumor cells after the photoactivation. For further development and novel applications of photodynamic therapy new photosensitizers are required. After synthesis of a new photosensitizer it is important to know its concentration in different biological tissues after its administration and distribution. The concentration is frequently measured by the extraction method, which has some disadvantages, e.g. it requires many biological test subjects that are euthanized during the measurement. We propose to measure the photosensitizer concentration in tissue by its fluorescence. For this purpose fluorescent standards were developed. The standards are robust and simple to produce; their fluorescence signal does not change with time. The fluorescence intensity of fluorescent standards seems to depend linearly on the dye concentration. A set of standards thus allow the calibration of a spectrometer. Finally, the photosensitizer concentration can be determined by the fluorescence intensity after comparing the corresponding spectrum with spectra of the set of fluorescent standards. A biological test subject is not euthanized during this kind of experiment. We hope this more humane technique can be used in future instead of the extraction method.

  10. Fluorescence molecular tomography in the presence of background fluorescence

    International Nuclear Information System (INIS)

    Soubret, Antoine; Ntziachristos, Vasilis

    2006-01-01

    Fluorescence molecular tomography is an emerging imaging technique that resolves the bio-distribution of engineered fluorescent probes developed for in vivo reporting of specific cellular and sub-cellular targets. The method can detect fluorochromes in picomole amounts or less, imaged through entire animals, but the detection sensitivity and imaging performance drop in the presence of background, non-specific fluorescence. In this study, we carried out a theoretical and an experimental investigation on the effect of background fluorescence on the measured signal and on the tomographic reconstruction. We further examined the performance of three subtraction methods based on physical models of photon propagation, using experimental data on phantoms and small animals. We show that the data pre-processing with subtraction schemes can improve image quality and quantification when non-specific background florescence is present

  11. The role of pars flaccida in human middle ear sound transmission.

    Science.gov (United States)

    Aritomo, H; Goode, R L; Gonzalez, J

    1988-04-01

    The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

  12. Apoplejía pituitaria con parálisis del III par craneal: Reporte de caso

    Directory of Open Access Journals (Sweden)

    Miguel Pinto Valdivia

    2011-10-01

    Full Text Available Se describe el caso de un varón de 65 años de edad, sin antecedentes patológicos de importancia, que acudió a emergencia del Hospital Nacional Cayetano Heredia por presentar cefalea intensa y ptosis palpebral izquierda. El examen físico mostró parálisis aislada del III par craneal izquierdo. Los análisis de laboratorio mostraron hiponatremia e hipopituitarismo y la resonancia magnética nuclear un adenoma pituitario con áreas de hemorragia e invasión de los senos cavernosos. El tratamiento incluyó glucocorticoides y descompresión quirúrgica transesfenoidal. La anatomía patológica confirmó el diagnóstico de infarto hemorrágico de un adenoma pituitario. El paciente fue dado de alta con terapia sustitutiva de levotiroxina y prednisona. La ptosis palpebral izquierda se recuperó en forma parcial. La apoplejía pituitaria es un síndrome clínico producido por un proceso expansivo dentro de la silla turca, secundario a hemorragia o infarto de un adenoma pituitario, que se caracteriza por cefalea, déficit visual, oftalmoplejía y alteración del nivel de conciencia. Este proceso expansivo puede comprimir los pares craneales en los senos cavernosos, produciendo diferentes grados de parálisis de los músculos oculomotores. La parálisis aislada del III par craneal es rara.(Rev Med Hered 2011;22:186-189.

  13. Instructive for disposal of fluorescent

    International Nuclear Information System (INIS)

    Salazar Vargas, Gerlin

    2014-01-01

    An instructive is established for the management system of waste fluorescent lamps, ensuring the storage, collection, transportation, and final disposal. The lamp is changed by an official of the Seccion de Matenimiento Construccion of the Oficina de Servicios Generales or is produced with the support of an official of the unit. The fluorescent should be deposited in stock of materials of the building maintenance section or unit specified with the help of a staff and in appropriate conditions. The fluorescent lamp is transported according to the guidelines in the manual. A responsible company is contracted by la Vicerrectoria de Administracion of the Universidad de Costa Rica dedicated to the transport and proper handling of fluorescent lamps [es

  14. ANTAGONISTIC POTENTIAL OF FLUORESCENT Pseudomonas ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    GROWTH OF TOMATO CHALLENGED WITH PHTOPATHOGENS ... This study focused on the antagonistic potential of fluorescent Pseudomonas in vitro, and its inoculation effect on growth .... the 5 days old culture in starch agar with Lugol's.

  15. Soluble urokinase plasminogen activator receptor (suPAR) in acute care

    DEFF Research Database (Denmark)

    Rasmussen, Line Jee Hartmann; Ladelund, Steen; Haupt, Thomas Huneck

    2016-01-01

    for age, sex, Charlson score and C reactive protein. Area under the curve for receiver operating characteristics curve analysis of suPAR for 30-day mortality was 0.84 (95% CI 0.81 to 0.86). Furthermore, in the entire cohort, women had slightly higher suPAR compared with men, and suPAR was associated...

  16. Movement and equipositioning of plasmids by ParA filament disassembly

    DEFF Research Database (Denmark)

    Ringgaard, Simon; van Zon, Jeroen; Howard, Martin

    2009-01-01

    , plasmids consistently migrate behind disassembling ParA cytoskeletal structures, suggesting that ParA filaments pull plasmids by depolymerization. The perpetual cycles of ParA assembly and disassembly result in continuous relocation of plasmids, which, on time averaging, results in equidistribution...

  17. Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

    Science.gov (United States)

    Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

    2018-02-14

    Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

  18. Protease-Activated Receptor 4 (PAR4: A Promising Target for Antiplatelet Therapy

    Directory of Open Access Journals (Sweden)

    Gamariel Rwibasira Rudinga

    2018-02-01

    Full Text Available Cardiovascular diseases (CVDs are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs, including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR. Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

  19. Par3L enhances colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway

    International Nuclear Information System (INIS)

    Li, Taiyuan; Liu, Dongning; Lei, Xiong; Jiang, Qunguang

    2017-01-01

    Partitioning defective 3-like protein (Par3L) is a recently identified cell polarity protein that plays an important role in mammary stem cell maintenance. Previously, we showed that high expression of Par3L is associated with poor survival in malignant colorectal cancer (CRC), but the underlying mechanism remained unknown. To this end, we established a Par3L knockout colorectal cancer cell line using the CRISPR/Cas system. Interestingly, reduced proliferation, enhanced cell death and caspase-3 activation were observed in Par3L knockout (KO) cells as compared with wildtype (WT) cells. Consistent with previous studies, we showed that Par3L interacts with a tumor suppressor protein liver kinase B1 (Lkb1). Moreover, Par3L depletion resulted in abnormal activation of Lkb1/AMPK signaling cascade. Knockdown of Lkb1 in these cells could significantly reduce AMPK activity and partially rescue cell death caused by Par3L knockdown. Furthermore, we showed that Par3L KO cells were more sensitive to chemotherapies and irradiation. Together, these results suggest that Par3L is essential for colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway, and is a putative therapeutic target for CRC. - Highlights: • Par3L knockout using the CRISPR/Cas system induces apoptosis in colorectal cancer cells. • Par3L interacts with Lkb1 and regulates the activity of AMPK signaling cascade. • Par3L knockout cells are more sensitive to treatment of different chemotherapy drugs and irradiation.

  20. Brésil : La contamination par le mercure en Amazonie | CRDI ...

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

    11 janv. 2011 ... En tentant de déceler la source de la contamination de l'Amazone par le ... par Jean-Rémy Davy Guimaraes de l'Université fédérale de Rio de Janeiro ... ces mattes est circonscrite par la conservation et la restauration en rive.

  1. X-ray fluorescence holography

    CERN Document Server

    Hayashi, K; Takahashi, Y

    2003-01-01

    X-ray fluorescence holography (XFH) is a new structural analysis method of determining a 3D atomic arrangement around fluorescing atoms. We developed an XFH apparatus using advanced X-ray techniques and succeeded in obtaining high-quality hologram data. Furthermore, we introduced applications to the structural analysis of a thin film and the environment around dopants and, discussed the quantitative analysis of local lattice distortion. (author)

  2. Fluorescent Nanodiamonds in Biomedical Applications.

    Science.gov (United States)

    Mitura, Katarzyna Anna; Włodarczyk, Elżbieta

    2018-04-18

    Nanoparticles have an extended surface and a large surface area, which is the ratio of the size of the surfacearea to the volume. A functionalized surface can give rise to more modifications and therefore allows this nanomaterial to have new properties. Fluorescent molecules contain fluorophore, which is capable of being excited via the absorption of light energy at a specific wavelength and subsequently emitting radiation energy of a longer wavelength. A chemically modified surface of nanodiamond (ND; by carboxylation) demonstrated biocompatibility with DNA, cytochrome C, and antigens. In turn, fluorescent nanodiamonds (FNDs) belong to a group of new nanomaterials. Their surface can be modified by joining functional groups such as carboxyl, hydroxyl, or amino, after which they can be employed as a fluorescence agent. Their fluorescent properties result from defects in the crystal lattice. FNDs reach dimensions of 4-100 nm, have attributes such as photostability, long fluorescence lifetimes (10 ns), and fluorescence emission between 600 and 700 nm. They are also nontoxic, chemically inert, biocompatible, and environmentally harmless. The main purpose of this article was to present the medical applications of various types of modified NDs.

  3. Fluorescence detection of esophageal neoplasia

    Science.gov (United States)

    Borisova, E.; Vladimirov, B.; Avramov, L.

    2008-06-01

    White-light endoscopy is well-established and wide used modality. However, despite the many technological advances that have been occurred, conventional endoscopy is suboptimal and usually detects advanced stage lesions. The limitations of standard endoscopy initiate development of spectroscopic techniques, additional to standard endoscopic equipment. One of the most sensitive approaches is fluorescence spectroscopy of gastrointestinal mucosa for neoplasia detection. In the recent study delta-aminolevulinic acid/Protoporphyrin IX (5-ALA/PpIX) is used as fluorescent marker for dysplasia and tumor detection in esophagus. The 5-ALA is administered per os six hours before measurements at dose 20 mg/kg weight. Excitation source has max of emission at 405 nm and light is delivered by the standard light guide of the endoscopic equipment. Through endoscopic instrumental channel a fiber is applied to return information about fluorescence to microspectrometer. Spectral features observed during endoscopic investigations could be distinct as the next regions: 450-630 nm region, where tissue autofluorescence is observed; 630-710 nm region, where fluorescence of PpIX is clearly pronounced; 530-580 nm region, where minima in the autofluorescence signal are observed, related to reabsorption of blood. The lack of fluorescence peaks in the red spectral area for normal mucosa is an indication for selective accumulation of 5-ALA/PpIX only in abnormal sites Very good correlation between fluorescence signals and histology examination of the lesions investigated is achieved.

  4. FLUORESCENCE DIAGNOSIS FOR RECURRENT BLADDER CANCER

    Directory of Open Access Journals (Sweden)

    R. V. Ulyanov

    2017-01-01

    Full Text Available The clinical case of successful use of local fluorescence spectroscopy combined with fluorescence imaging during cystoscopy for diagnosis of recurrent bladder cancer is represented in the article. Histological study of fluorescent foci confirmed tumor growth (urothelial carcinoma in all areas with high levels of diagnostic parameter. In the fluorescent focus with low diagnostic parameter inflammation was detected.

  5. La syphilis congenitale revelee par une fracture spontanee

    Directory of Open Access Journals (Sweden)

    Mounia Lakhdar Idrissi

    2011-11-01

    Full Text Available Alors qu�elle est actuellement oubliee dans les pays developpes, la syphilis congenitale se voit encore chez nous faute du depistage antenatal. Ses formes cliniques sont polymorphes et orientent a tord vers d�autres pathologies surtout en periode neonatale. Le diagnostic n�est donc pas toujours facile. La revelation d�une syphilis congenitale par une fracture spontanee est exceptionnellement decrite. Nous rapportons dans ce travail le cas d�un nourrisson de 2 mois ramene en consultation pour limitation douloureuse des mouvements du bras droit. Le diagnostic est evoque sur les donnees radiologiques et confirme par la serologie syphilitique. Le traitement a repose essentiellement sur l�administration de la penicilline G avec une bonne evolution clinique.

  6. Results of Preliminary Tests of PAR Bunch Cleaning

    CERN Document Server

    Yao, Chihyuan; Grelick, Arthur; Lumpkin, Alex H; Sereno, Nicholas S

    2005-01-01

    A particle accumulator ring (PAR) is used at the Advanced Photon Source (APS) to collect multiple linac bunches and compress them into a 0.3-ns (rms) single bunch for booster injection. A 9.77-MHz fundamental rf system and a 117.3-MHz harmonic rf system are employed for initial beam capture and bunch length compression. Satellite bunches with very low charge form due to rf phase drifts or beam loading change. These satellites, when injected into the booster and then into the storage ring (SR), cause bunch impurity at three buckets from the target bucket. Storage ring and booster bunch cleaning was tried but proved to be difficult due to the top-up mode of operation in the storage ring and tune drift in the booster synchrotron. Recently we implemented a PAR bunch-cleaning system with tune-modulated harmonic rf knockout. Preliminary tests gave a measured SR bunch purity of better than 10

  7. Avis 6 sur la formation à et par la recherche

    OpenAIRE

    Centre de Coopération Internationale en Recherche Agronomique pour le Développement

    2015-01-01

    La formation à et par la recherche s’appuie sur la démarche scientifique, les savoirs, les connaissances à transmettre, tout autant que l’acquisition de compétences en gestion de projet, de capacités au travail en équipe, d’une ouverture d’esprit qui favorisera la créativité. Elle doit permettre de prendre conscience de la responsabilité endossée par la communauté scientifique vis-à-vis de la société et de l’environnement, mais aussi préparer l’avenir professionnel de celle ou de celui qu...

  8. Evaluation of the Stability After Orthodontic Treatment Using PAR Index

    Directory of Open Access Journals (Sweden)

    Chaitra Ramanathan

    2006-01-01

    Full Text Available The aim of the present study is to establish the results using the scores obtained from the methodology that was applied for assessing the stability after 2 years post orthodontic treatment and stability in a sample of 69 individuals. After applying PAR index to the collected group of patients, a series of scores were obtained, which were then needed to be evaluated further to establish the results. The scores were evaluated using the nomogram. A comparison was done between the post treatment and the 2 years post treatment PAR weighting scores to determine if the results were stable after orthodontic treatment. The majority of the orthodontic patients were treated to a good standard and that the results appeared to be stable.

  9. La parálisis cerebral en el contexto escolar /

    OpenAIRE

    González Vara, Azucena

    2012-01-01

    Se analiza el concepto de parálisis cerebral, los diferentes tipos y sus características. También las adaptaciones que se deben realizar a nivel de centro, de aula, y a nivel individual para estos alumnos, conocer los diferentes sistemas alternativos y aumentativos de comunicación y aplicar las ayudas técnicas que precisa este alumnado

  10. Tuberculose lymphonodale cervicale chez les enfants vaccines par ...

    African Journals Online (AJOL)

    La tuberculose ganglionnaire cervicale est une localisation extrapulmonaire relativement fréquente chez l'enfant. Elle pose essentiellement des difficultés de prévention. L'objectif de ce travail est d'étudier les particularités diagnostiques et thérapeutiques chez des enfants vaccinés par le BCG. Matériel et méthodes: Nôtre ...

  11. Traitement De La Peripneumonie Contagieuse Bovine Par L ...

    African Journals Online (AJOL)

    Traitement De La Peripneumonie Contagieuse Bovine Par L'oxyteTracycline Longe Action Et Transmission Experimentale de la Maladie A Partir de Bovins Traites. ... Tous les 14 animaux ont séroconverti et l'analyse post-mortem a montré la présence des lésions chroniques dont des séquestres pulmonaires chez 4 d'entre ...

  12. Adoption d'innovations agricoles par le truchement de services ...

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

    L'agriculture est le fer de lance de nombreuses économies en développement, mais la capacité des petits agriculteurs privés de ressources à adopter des innovations agricoles est freinée par le manque d'accès à des services financiers adéquats. Des experts internationaux estiment qu'il existe un manque à gagner ...

  13. Candido: Uma Leitura Paródica de Candide

    Directory of Open Access Journals (Sweden)

    Maria Gloria Cusumano Mazzi

    2010-12-01

    Full Text Available O presente artigo estuda a leitura paródica que Leonardo Sciascia (1921-1989 faz de Voltaire (1694-1778 mediante o cotejo das obras: o hipertexto Candido ovvero Un sogno fatto in Sicilia (1977 e o hipotexto Candide ou l’optimisme (1759. Apresenta ainda outra possibilidade de leitura, ou seja, Candido como metáfora da própria intertextualidade.

  14. Solution volumes finis polynomiale par morceaux pour les ...

    African Journals Online (AJOL)

    Nous présentons dans ce papier un concept de solution volumes finis continue pour des problèmes de diffusion-convection avec des données régulières. Nous comparons dans certains cas particuliers la solution proposée avec la solution volumes finis classiques (qui est une fonction constante par morceaux) et la ...

  15. Preliminary Analysis For Wolsong Par Effects Using ISACC Calculations

    International Nuclear Information System (INIS)

    Song, Yong Mann; Kim, Dong Ha

    2012-01-01

    In the paper, hydrogen control effects using PARs only are analyzed for severe SBO station blackout (SBO) sequences beyond the design basis accidents in WS-1 which are of CANDU6 type reactor. As a computational tool, the latest version of ISAAC4.3 (Integrated Severe Accident Analysis Code for CANDU), which is a fully integrated and lumped severe accident computer code, is used to simulate hydrogen generation and transport inside the reactor building (R/B) before its failure. For the performance of hydrogen removal, the depletion rate equation of K-PAR developed in Korea is applied. In a CANDU reactor, three areas are identified as sources of hydrogen under severe accidents: fuel-coolant interactions in intact channels, suspended fuel or debris interactions in-calandria tank and debris interactions in-calandria vault. The first two origins provide source for the late ('late' terminology is used because it takes more than one day before calandria tank failure) potential hydrogen combustion before calandria tank failure and all the three origins would provide source for the very late potential hydrogen combustion occurring at or after calaria tank failure. If the hydrogen mitigation system fails, the AICC (adiabatic isochoric complete combustion) burning of highly flammable hydrogen may cause Wolsong R/B failure. So hydrogen induced failure possibility is evaluated, using preliminary ISAAC calculations, under several SBO conditions with and without PAR for both late and very late accident periods

  16. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Silva, Jose Alberto Alves da

    2009-01-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH 2 , respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  17. First (18)F-labeled ligand for PET imaging of uPAR

    DEFF Research Database (Denmark)

    Persson, Morten; Liu, Hongguang; Madsen, Jacob

    2013-01-01

    Urokinase-type plasminogen activator receptor (uPAR) is overexpressed in human prostate cancer and uPAR has been found to be associated with metastatic disease and poor prognosis. AE105 is a small linear peptide with high binding affinity to uPAR. We synthesized an N-terminal NOTA......-conjugated version (NOTA-AE105) for development of the first (18)F-labeled uPAR positron-emission-tomography PET ligand using the Al(18)F radiolabeling method. In this study, the potential of (18)F-AlF-NOTA-AE105 to specifically target uPAR-positive prostate tumors was investigated....

  18. Intact and cleaved uPAR forms: diagnostic and prognostic value in cancer

    DEFF Research Database (Denmark)

    Rasch, M.G.; Lund, I.K.; Hoyer-Hansen, G.

    2008-01-01

    identified in tissue and body fluids. It is well-established, that the total amount of all uPAR forms is a strong prognostic marker in different types of cancer. Using immunoassays, measuring the individual uPAR forms, has revealed that the cleaved uPAR forms are even stronger prognostic markers and have...... diagnostic utility. This review will focus on the mechanism of uPAR cleavage and the functional consequences, as well as the clinical applicability of cleaved uPAR forms Udgivelsesdato: 2008...

  19. Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

    Directory of Open Access Journals (Sweden)

    Nicole Bäumer

    Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

  20. Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

    Science.gov (United States)

    Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

    2014-01-01

    External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

  1. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan; Acuna, Guillermo; Kim, Seungkyeum; Vietz, Carolin; Tseng, Derek; Chae, Jongjae; Shir, Daniel; Luo, Wei; Tinnefeld, Philip; Ozcan, Aydogan

    2017-01-01

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  2. Fluorescence and phosphorescence of rutin

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, Stanislav L., E-mail: bondarev@imaph.bas-net.by [Minsk State Higher Radioengineering College, 220005 Minsk (Belarus); Knyukshto, Valeri N. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 220072 Minsk (Belarus)

    2013-10-15

    Rutin is one of the most promising flavonoid from a pharmacological and biochemical point of view. Here we have explored its spectroscopic and photophysical properties at room temperature and 77 K using steady-state absorption-luminescence methods and pulse spectroscopy equipment. By excitation into the absorption band 1 of rutin in methanol at room temperature the normal Stokes' shifted fluorescence with a maximum at 415 nm and quantum yield of 2×10{sup −4} was revealed. However, by excitation into the bands 2 and 3 any emission wasn’t observed. At 77 K in ethanol glass we have observed fluorescence at 410 nm and phosphorescence at 540 nm for the first time. As a result the adequate energetic scheme including the lowest electronic excited singlet at 26000 cm{sup −1} and triplet at 19600 cm{sup −1} states was proposed. -- Highlights: • Rutin fluorescence and phosphorescence at 77 K were revealed for the first time. • Room temperature fluorescence is determined by maximum at 415 nm and yield of 2×10{sup −4}. • Violation of Vavilov–Kasha rule by excitation into the absorption bands 2 and 3. • Fluorescence and phosphorescence in rutin are caused by the allowed π, π{sup (⁎)} transitions.

  3. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan

    2017-05-12

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  4. The double par locus of virulence factor pB171: DNA segregation is correlated with oscillation of ParA

    DEFF Research Database (Denmark)

    Ebersbach, G; Gerdes, K; Charbon, Gitte Ebersbach

    2001-01-01

    Prokaryotic plasmids and chromosomes encode partitioning (par) loci that segregate DNA to daughter cells before cell division. Recent database analyses showed that almost all known par loci encode an ATPase and a DNA-binding protein, and one or more cis-acting regions where the proteins act. All...

  5. Fluorescence confocal microscopy for pathologists.

    Science.gov (United States)

    Ragazzi, Moira; Piana, Simonetta; Longo, Caterina; Castagnetti, Fabio; Foroni, Monica; Ferrari, Guglielmo; Gardini, Giorgio; Pellacani, Giovanni

    2014-03-01

    Confocal microscopy is a non-invasive method of optical imaging that may provide microscopic images of untreated tissue that correspond almost perfectly to hematoxylin- and eosin-stained slides. Nowadays, following two confocal imaging systems are available: (1) reflectance confocal microscopy, based on the natural differences in refractive indices of subcellular structures within the tissues; (2) fluorescence confocal microscopy, based on the use of fluorochromes, such as acridine orange, to increase the contrast epithelium-stroma. In clinical practice to date, confocal microscopy has been used with the goal of obviating the need for excision biopsies, thereby reducing the need for pathological examination. The aim of our study was to test fluorescence confocal microscopy on different types of surgical specimens, specifically breast, lymph node, thyroid, and colon. The confocal images were correlated to the corresponding histological sections in order to provide a morphologic parallel and to highlight current limitations and possible applications of this technology for surgical pathology practice. As a result, neoplastic tissues were easily distinguishable from normal structures and reactive processes such as fibrosis; the use of fluorescence enhanced contrast and image quality in confocal microscopy without compromising final histologic evaluation. Finally, the fluorescence confocal microscopy images of the adipose tissue were as accurate as those of conventional histology and were devoid of the frozen-section-related artefacts that can compromise intraoperative evaluation. Despite some limitations mainly related to black/white images, which require training in imaging interpretation, this study confirms that fluorescence confocal microscopy may represent an alternative to frozen sections in the assessment of margin status in selected settings or when the conservation of the specimen is crucial. This is the first study to employ fluorescent confocal microscopy on

  6. Fluorescence detection of dental calculus

    Science.gov (United States)

    Gonchukov, S.; Biryukova, T.; Sukhinina, A.; Vdovin, Yu

    2010-11-01

    This work is devoted to the optimization of fluorescence dental calculus diagnostics in optical spectrum. The optimal wavelengths for fluorescence excitation and registration are determined. Two spectral ranges 620 - 645 nm and 340 - 370 nm are the most convenient for supra- and subgingival calculus determination. The simple implementation of differential method free from the necessity of spectrometer using was investigated. Calculus detection reliability in the case of simple implementation is higher than in the case of spectra analysis at optimal wavelengths. The use of modulated excitation light and narrowband detection of informative signal allows us to decrease essentially its diagnostic intensity even in comparison with intensity of the low level laser dental therapy.

  7. ParABS Systems of the Four Replicons of Burkholderia cenocepacia: New Chromosome Centromeres Confer Partition Specificity†

    Science.gov (United States)

    Dubarry, Nelly; Pasta, Franck; Lane, David

    2006-01-01

    Most bacterial chromosomes carry an analogue of the parABS systems that govern plasmid partition, but their role in chromosome partition is ambiguous. parABS systems might be particularly important for orderly segregation of multipartite genomes, where their role may thus be easier to evaluate. We have characterized parABS systems in Burkholderia cenocepacia, whose genome comprises three chromosomes and one low-copy-number plasmid. A single parAB locus and a set of ParB-binding (parS) centromere sites are located near the origin of each replicon. ParA and ParB of the longest chromosome are phylogenetically similar to analogues in other multichromosome and monochromosome bacteria but are distinct from those of smaller chromosomes. The latter form subgroups that correspond to the taxa of their hosts, indicating evolution from plasmids. The parS sites on the smaller chromosomes and the plasmid are similar to the “universal” parS of the main chromosome but with a sequence specific to their replicon. In an Escherichia coli plasmid stabilization test, each parAB exhibits partition activity only with the parS of its own replicon. Hence, parABS function is based on the independent partition of individual chromosomes rather than on a single communal system or network of interacting systems. Stabilization by the smaller chromosome and plasmid systems was enhanced by mutation of parS sites and a promoter internal to their parAB operons, suggesting autoregulatory mechanisms. The small chromosome ParBs were found to silence transcription, a property relevant to autoregulation. PMID:16452432

  8. Biomolecule-to-fluorescent-color encoder: modulation of fluorescence emission via DNA structural changes

    Science.gov (United States)

    Nishimura, Takahiro; Ogura, Yusuke; Yamada, Kenji; Ohno, Yuko; Tanida, Jun

    2014-01-01

    A biomolecule-to-fluorescent-color (B/F) encoder for optical readout of biomolecular information is proposed. In the B/F encoder, a set of fluorescence wavelengths and their intensity levels are used for coding of a biomolecular signal. A hybridization chain reaction of hairpin DNAs labeled with fluorescent reporters was performed to generate the fluorescence color codes. The fluorescence is modulated via fluorescence resonance energy transfer, which is controlled by DNA structural changes. The results demonstrate that fluorescent color codes can be configured based on two wavelengths and five intensities using the B/F encoder, and the assigned codes can be retrieved via fluorescence measurements. PMID:25071950

  9. Serum suPAR in patients with FSGS: trash or treasure?

    Science.gov (United States)

    Maas, Rutger J H; Deegens, Jeroen K J; Wetzels, Jack F M

    2013-07-01

    The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both overexpression of uPAR on podocytes and the administration of suPAR cause proteinuria in mice. The common pathogenic mechanism involves the activation of podocyte β3-integrin. Increased activation of β3-integrin is also observed in patients with focal and segmental glomerulosclerosis (FSGS). These observations form the basis for the hypothesis that suPAR may be the circulating factor causing FSGS. A recent study fosters this idea by demonstrating increased suPAR levels in the serum of patients with FSGS and reporting an association with recurrence after transplantation and response to plasmapheresis. However, this study was heavily biased, and subsequent studies have given conflicting results. Although the experimental work is very suggestive, at present there is no proof that any known human suPAR fragment causes FSGS in humans. We therefore suggest that the measurement of suPAR using currently available assays has absolutely no value at the present time in decision-making in routine clinical practice.

  10. PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity

    Directory of Open Access Journals (Sweden)

    Henrique FUKUSHIMA

    Full Text Available Abstract Recent studies investigating protease-activated receptor type 2 (PAR-2 suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF of patients with moderate chronic periodontitis (MP. The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19 at baseline, and from MP patients (n = 19 and severe chronic periodontitis (SP (n = 19 patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR. PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p <0.05 PAR-2 expression in patients with periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

  11. Structures of actin-like ParM filaments show architecture of plasmid-segregating spindles.

    Science.gov (United States)

    Bharat, Tanmay A M; Murshudov, Garib N; Sachse, Carsten; Löwe, Jan

    2015-07-02

    Active segregation of Escherichia coli low-copy-number plasmid R1 involves formation of a bipolar spindle made of left-handed double-helical actin-like ParM filaments. ParR links the filaments with centromeric parC plasmid DNA, while facilitating the addition of subunits to ParM filaments. Growing ParMRC spindles push sister plasmids to the cell poles. Here, using modern electron cryomicroscopy methods, we investigate the structures and arrangements of ParM filaments in vitro and in cells, revealing at near-atomic resolution how subunits and filaments come together to produce the simplest known mitotic machinery. To understand the mechanism of dynamic instability, we determine structures of ParM filaments in different nucleotide states. The structure of filaments bound to the ATP analogue AMPPNP is determined at 4.3 Å resolution and refined. The ParM filament structure shows strong longitudinal interfaces and weaker lateral interactions. Also using electron cryomicroscopy, we reconstruct ParM doublets forming antiparallel spindles. Finally, with whole-cell electron cryotomography, we show that doublets are abundant in bacterial cells containing low-copy-number plasmids with the ParMRC locus, leading to an asynchronous model of R1 plasmid segregation.

  12. PAR-1 contributes to the innate immune response during viral infection

    Science.gov (United States)

    Antoniak, Silvio; Owens, A. Phillip; Baunacke, Martin; Williams, Julie C.; Lee, Rebecca D.; Weithäuser, Alice; Sheridan, Patricia A.; Malz, Ronny; Luyendyk, James P.; Esserman, Denise A.; Trejo, JoAnn; Kirchhofer, Daniel; Blaxall, Burns C.; Pawlinski, Rafal; Beck, Melinda A.; Rauch, Ursula; Mackman, Nigel

    2013-01-01

    Coagulation is a host defense system that limits the spread of pathogens. Coagulation proteases, such as thrombin, also activate cells by cleaving PARs. In this study, we analyzed the role of PAR-1 in coxsackievirus B3–induced (CVB3-induced) myocarditis and influenza A infection. CVB3-infected Par1–/– mice expressed reduced levels of IFN-β and CXCL10 during the early phase of infection compared with Par1+/+ mice that resulted in higher viral loads and cardiac injury at day 8 after infection. Inhibition of either tissue factor or thrombin in WT mice also significantly increased CVB3 levels in the heart and cardiac injury compared with controls. BM transplantation experiments demonstrated that PAR-1 in nonhematopoietic cells protected mice from CVB3 infection. Transgenic mice overexpressing PAR-1 in cardiomyocytes had reduced CVB3-induced myocarditis. We found that cooperative signaling between PAR-1 and TLR3 in mouse cardiac fibroblasts enhanced activation of p38 and induction of IFN-β and CXCL10 expression. Par1–/– mice also had decreased CXCL10 expression and increased viral levels in the lung after influenza A infection compared with Par1+/+ mice. Our results indicate that the tissue factor/thrombin/PAR-1 pathway enhances IFN-β expression and contributes to the innate immune response during single-stranded RNA viral infection. PMID:23391721

  13. Par-4-mediated recruitment of Amida to the actin cytoskeleton leads to the induction of apoptosis

    International Nuclear Information System (INIS)

    Boosen, Meike; Vetterkind, Susanne; Koplin, Ansgar; Illenberger, Susanne; Preuss, Ute

    2005-01-01

    Par-4 (prostate apoptosis response-4) sensitizes cells to apoptotic stimuli, but the exact mechanisms are still poorly understood. Using Par-4 as bait in a yeast two-hybrid screen, we identified Amida as a novel interaction partner, a ubiquitously expressed protein which has been suggested to be involved in apoptotic processes. Complex formation of Par-4 and Amida occurs in vitro and in vivo and is mediated via the C-termini of both proteins, involving the leucine zipper of Par-4. Amida resides mainly in the nucleus but displays nucleo-cytoplasmic shuttling in heterokaryons. Upon coexpression with Par-4 in REF52.2 cells, Amida translocates to the cytoplasm and is recruited to actin filaments by Par-4, resulting in enhanced induction of apoptosis. The synergistic effect of Amida/Par-4 complexes on the induction of apoptosis is abrogated when either Amida/Par-4 complex formation or association of these complexes with the actin cytoskeleton is impaired, indicating that the Par-4-mediated relocation of Amida to the actin cytoskeleton is crucial for the pro-apoptotic function of Par-4/Amida complexes in REF52.2 cells. The latter results in enhanced phosphorylation of the regulatory light chain of myosin II (MLC) as has previously been shown for Par-4-mediated recruitment of DAP-like kinase (Dlk), suggesting that the recruitment of nuclear proteins involved in the regulation of apoptotic processes to the actin filament system by Par-4 represents a potent mechanism how Par-4 can trigger apoptosis

  14. Bacterial mitosis: Partitioning protein ParA oscillates in spiral-shaped structures and positions plasmids at mid-cell

    DEFF Research Database (Denmark)

    Ebersbach, G.; Gerdes, Kenn

    2004-01-01

    The par2 locus of Escherichia coli plasmid pB171 encodes oscillating ATPase ParA, DNA binding protein ParB and two cis-acting DNA regions to which ParB binds (parC1 and parC2). Three independent techniques were used to investigate the subcellular localization of plasmids carrying par2. In cells......A-GFP oscillated in spiral-shaped structures. Amino acid substitutions in ParA simultaneously abolished ParA spiral formation, oscillation and either plasmid localization or plasmid separation at mid-cell. Therefore, our results suggest that ParA spirals position plasmids at the middle of the bacterial nucleoid...

  15. Envenimation mortelle par morsure de serpent chez une femme ...

    African Journals Online (AJOL)

    Les auteurs rapportent un cas de morsure de serpent au niveau de la face chez une femme enceinte, dont l'évolution a été marquée par l'installation d'un oedème cervico-facial nécessitant une trachéotomie en urgence, et une mort foetale in utero avec troubles de l'hémostase responsable du décès maternel dans un ...

  16. Analysis of clinical features and visual outcomes of pars planitis.

    Science.gov (United States)

    Berker, Nilufer; Sen, Emine; Elgin, Ufuk; Atilgan, Cemile Ucgul; Dursun, Erdem; Yilmazbas, Pelin

    2018-04-01

    To evaluate the demographic characteristics, clinical features, treatment and outcomes of patients with pars planitis in a tertiary referral center in Turkey. Medical records of patients with pars planitis were retrospectively reviewed. The data including demographic and ocular features and treatment outcomes were recorded. The distribution of clinical findings and complications were evaluated according to age and gender groups. The changes in final BCVA compared to the initial BCVA were noted. Statistical analysis was performed using SPSS software (Version 18.0, SPSS Inc., Chicago, USA). Twenty-seven patients (54 eyes) were included in this study. 16 patients were male (59.3%), and 11 were female (40.7%). Mean age at diagnosis was 12.84 ± 8.26 (range 4-36) years. Mean follow-up period was 61.3 ± 52.15 (range 9-172) months. Mean BCVA was 0.58 ± 0.36 (range 0.03-1.00) (0.40 ± 0.45 logMAR) at presentation, and 0.81 ± 0.28 (range 0.10-1.00) (0.14 ± 0.27 logMAR) at final visit (P = 0.001). Vitreous inflammation (100%), vitreous haze (92.6%), snowballs (74.1%), snowbanks (66.7%), anterior chamber cells (66.7%) and peripheral retinal vascular sheathing (48.1%) were the most common presentations. Ocular complications included vitreous condensation (51.9%), cystoid macular edema (22.2%), cataract (18.5%), inferior peripheral retinal detachment (11.1%), glaucoma (5.6%) and vitreous hemorrhage (3.7%). Treatments included topical, periocular, intravitreal and systemic corticosteroids, immunosuppressives, peripheral laser photocoagulation and pars plana vitrectomy when needed. Pars planitis is an idiopathic chronic intermediate uveitis mostly affecting children and adolescents. In spite of its chronic nature with high potential of causing ocular complications, adequate treatment and close follow-up lead to favorable visual outcomes.

  17. Cartographie par carroyage et précision spatiale

    Directory of Open Access Journals (Sweden)

    Patrice LANGLOIS

    1998-03-01

    Full Text Available Dans le cadre d'une cartographie par carroyage, on étudie la désagrégation de variables zonales, en revenant sur l'hypothèse de l'équirépartition spatiale des populations. L'objectif est d'approcher des règles différenciées de désagrégation des variables en fusionnant des plans d'information de nature morphologique, topologique et environnementale.

  18. X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Vries, J.L. de.

    1976-01-01

    The seventh edition of Philips' Review of Literature on x-ray fluorescence spectrometry starts with a list of conference proceedings on the subject, organised by the Philips organisation at regular intervals in various European countries. It is followed by a list of bulletins. The bibliography is subdivided according to spectra, equipment, applications and absorption analysis

  19. X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Ray, N.B.

    1977-01-01

    The principle, instrument and procedure of X-ray fluorescence spectrometry are described. It is a rapid, simple and sensitive method for the trace analysis of elements from sodium to uranium in powder, liquid or metal samples. (M.G.B.)

  20. A fluorescent probe for ecstasy.

    Science.gov (United States)

    Masseroni, D; Biavardi, E; Genovese, D; Rampazzo, E; Prodi, L; Dalcanale, E

    2015-08-18

    A nanostructure formed by the insertion in silica nanoparticles of a pyrene-derivatized cavitand, which is able to specifically recognize ecstasy in water, is presented. The absence of effects from interferents and an efficient electron transfer process occurring after complexation of ecstasy, makes this system an efficient fluorescent probe for this popular drug.

  1. Erythrocyte fluorescence and lead intoxication.

    Science.gov (United States)

    Clark, K G

    1976-01-01

    Blood samples from people exposed to inorganic lead were examined by fluorescence microscopy for excess erythrocyte porphyrin. With continued lead absorption, fluorescent erythrocytes appeared in the circulation of workers handling this metal or its compounds, and they progressively increased in number and brilliance. These changes ensued if the blood lead concentration was maintained above 2-42 mumol/l (50 mug/100 ml), and preceded any material fall in the haemoglobin value. At one factory, 62-5% of 81 symptomless workers showed erythrocyte fluorescence attributable to the toxic effects of lead. Excess fluorocytes were found in blood samples from a child with pica and three of her eight siblings. These four were subsequently shown to have slightly increased blood lead concentrations (2-03 to 2-32 mumol/l). Fluorescence microscopy for excess erythrocyte porphyrin is a sensitive method for the detection of chronic lead intoxication. A relatively slight increase in the blood lead is associated with demonstrabel changes in erythrocyte porphyrin content. The procedure requires little blood, and may be performed upon stored samples collected for lead estimation. The results are not readily influenced by contamination, and provide good confirmatory evidence for the absorption of biochemically active lead. PMID:963005

  2. Fluorescent sensors based on bacterial fusion proteins

    International Nuclear Information System (INIS)

    Mateu, Batirtze Prats; Pum, Dietmar; Sleytr, Uwe B; Toca-Herrera, José L; Kainz, Birgit

    2014-01-01

    Fluorescence proteins are widely used as markers for biomedical and technological purposes. Therefore, the aim of this project was to create a fluorescent sensor, based in the green and cyan fluorescent protein, using bacterial S-layers proteins as scaffold for the fluorescent tag. We report the cloning, expression and purification of three S-layer fluorescent proteins: SgsE-EGFP, SgsE-ECFP and SgsE-13aa-ECFP, this last containing a 13-amino acid rigid linker. The pH dependence of the fluorescence intensity of the S-layer fusion proteins, monitored by fluorescence spectroscopy, showed that the ECFP tag was more stable than EGFP. Furthermore, the fluorescent fusion proteins were reassembled on silica particles modified with cationic and anionic polyelectrolytes. Zeta potential measurements confirmed the particle coatings and indicated their colloidal stability. Flow cytometry and fluorescence microscopy showed that the fluorescence of the fusion proteins was pH dependent and sensitive to the underlying polyelectrolyte coating. This might suggest that the fluorescent tag is not completely exposed to the bulk media as an independent moiety. Finally, it was found out that viscosity enhanced the fluorescence intensity of the three fluorescent S-layer proteins. (paper)

  3. Physiological bases for detecting and predicting photoinhibition of aquatic photosynthesis by PAR and UV radiation

    International Nuclear Information System (INIS)

    Neale, P.J.; Cullen, J.J.; Lesser, M.P.; Melis, A.

    1993-01-01

    stress is usually time dependent (12, 36); the light history of the cells must be known to specify the overall effect. The established method for measuring phytoplankton production, photosynthetic incorporation of 14 C into organic carbon during a12-24 h bottle incubation, may seriously misrepresent irradiance regimes actually experienced by phytoplankton in situ. Further discussion of the interaction of photoinhibition and mixing can be found in (36).We propose that an integrated modeling-sampling approach is needed to define the effects of irradiance stress on productivity in situ. The model should incorporate an optical specification of the underwater irradiance environment, abiological weighting function to account for the wavelength-dependence of photoinhibition of photosynthesis, and a response function of biological action during vertical mixing to account for the differences between static incubations and natural movements of phytoplankton. Recently, excellent progress has been made toward defining the individual components of this model (See also Cullen and Neale, this volume). To verify the model, we need to detect reliably the occurrence of irradiance stress in situ. This is the sampling side of the integrated approach. In particular, we would like to differentiate between the effects of PAR and UV. We propose that such detection can be accomplished by indicator assays (or ''diagnostic markers''). Such assays would involve little or no incubation of samples, so that the measurement corresponds as closely as possible to the physiological state of the phytoplankton at time of sampling.Our objective here is to review selected aspects of irradiance stress at biophysical and molecular levels, and then proceed to examine how that information can be used to design indicator assays of irradiance stress for phytoplankton photosynthesis in situ. The effects of PAR and UV at the cellular level and the use of in vivo fluorescence and molecular probes

  4. Excited state fluorescence quenching of the U O2++ ion by monovalent anions

    International Nuclear Information System (INIS)

    Santarine, G.A.

    1987-01-01

    The reactions of the Uranyl ion U O 2 ++ in the excited state with the monovalent inorganic ions N O 3 - and I O 3 - in aqueous solutions at normal temperature were studied, using three techniques: Fluorescence in the steady state - Flash photolysis - Fluorescence decay after excitation. With increasing concentration of these ions it was observed a decrease in the normalized intensity and a decrease in the decay time of the fluorescence of the Uranyl ion in the solution and a corresponding appearance of the radicals N O 3 . or I O 3 . . In each case the radical was identified by its optical absorption spectrum. These results suggest that the quenching of fluorescence of the Uranyl ion in each case is owing to an electron transfer reaction. In the case of the Nitrate ion the transfer may occur after the formation of an ionic par (U O 2 + ...N O 3 ) in the ground state. Evidence for static quenching in the system Uranyl iodate was not forthcoming. A mechanism for the determination of the velocity constant (probability per ion pair per unit time) is proposed for each of the systems. (author)

  5. PET imaging of urokinase-type plasminogen activator receptor (uPAR) in prostate cancer

    DEFF Research Database (Denmark)

    Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

    2016-01-01

    Overexpression of urokinase-type plasminogen activator receptors (uPAR) represents an important biomarker for aggressiveness in most common malignant diseases, including prostate cancer (PC). Accordingly, uPAR expression either assessed directly in malignant PC tissue or assessed directly in plasma...... and prognostic imaging method. In this review, we will focus on the recent development of uPAR PET and the relevance within prostate cancer imaging. Novel antibody and small-molecule radiotracers-targeting uPAR, including a series of uPAR-targeting PET ligands, based on the high affinity peptide ligand AE105......, have been synthesized and tested in vitro and in vivo in preclinical murine xenograft models and, recently, in a first-ever clinical uPAR PET study in cancer patients, including patients with PC. In this phase I study, a high and specific uptake of the tracer 64Cu-DOTA-AE105 was found in both primary...

  6. Paracrine Apoptotic Effect of p53 Mediated by Tumor Suppressor Par-4

    Directory of Open Access Journals (Sweden)

    Ravshan Burikhanov

    2014-01-01

    Full Text Available The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53−/− or Par-4−/− mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 induced Par-4 secretion by suppressing the expression of its binding partner, UACA, which sequesters Par-4. Thus, normal cells can be empowered by p53 activation to induce Par-4 secretion for the inhibition of therapy-resistant tumors.

  7. Fluorescent Protein Approaches in Alpha Herpesvirus Research

    Directory of Open Access Journals (Sweden)

    Ian B. Hogue

    2015-11-01

    Full Text Available In the nearly two decades since the popularization of green fluorescent protein (GFP, fluorescent protein-based methodologies have revolutionized molecular and cell biology, allowing us to literally see biological processes as never before. Naturally, this revolution has extended to virology in general, and to the study of alpha herpesviruses in particular. In this review, we provide a compendium of reported fluorescent protein fusions to herpes simplex virus 1 (HSV-1 and pseudorabies virus (PRV structural proteins, discuss the underappreciated challenges of fluorescent protein-based approaches in the context of a replicating virus, and describe general strategies and best practices for creating new fluorescent fusions. We compare fluorescent protein methods to alternative approaches, and review two instructive examples of the caveats associated with fluorescent protein fusions, including describing several improved fluorescent capsid fusions in PRV. Finally, we present our future perspectives on the types of powerful experiments these tools now offer.

  8. Vegetation Function and Physiology: Photosynthesis, Fluorescence and Non-photochemical Quenching (NPQ)

    Science.gov (United States)

    Zhang, Q.; Yao, T.

    2017-12-01

    Photosynthesis is a basic physiological function of vegetation that relies on PAR provided through photosynthetic pigments (mainly chlorophyll) for plant growth and biomass accumulation. Vegetation chlorophyll (chl) content and non-chlorophyll (non-chl) components vary with plant functional types (PFTs) and growing stages. The PAR absorbed by canopy chlorophyll (APARchl) is associated with photosynthesis (i.e., gross primary production, GPP) while the PAR absorbed by canopy non-chl components (APARnon-chl) is not associated with photosynthesis. Under non-optimal environmental conditions, vegetation is "stressed" and both photosynthesis (GPP) and light use efficiency are reduced, therefore, excess portions of APARchl are discarded as fluorescence or non-photochemical quenching (NPQ). The photochemical reflectance index (PRI) is a measurement related to NPQ. Both PRI and yield of solar induced chlorophyll fluorescence (SIFyield = SIF/APARchl) have been proposed as possible bio-indicators of LUEchl. We have successfully developed an algorithm to distinguish between chlorophyll and non-chl components of vegetation, and to retrieve fractional absorptions of PAR by chlorophyll (fAPARchl) and by non-chl components (fAPARnon-chl) with surface reflectance of MODIS bands 1 - 7. A method originally pioneered by Hanan et al. (2002) has been used to retrieve fAPAR for vegetation photosynthesis (fAPARPSN) at flux tower sites based on the light response curve of tower net ecosystem exchange (NEE) and incident PAR at low light intensity. We have also retrieved the PRI from MODIS data (bands 11 and 1) and have derived SIFyield with the Global Ozone Monitoring Experiment - 2 (GOME-2) SIF data. We find that fAPARPSN at flux tower sites matches well with site fAPARchl, and ratio fAPARnon-chl/fAPARchl varies largely. APARchl can explain >=78% variation in seasonal GPP . We disentangle the possible impact of fAPARchl on PRI from physiological stress response, disentangle the possible

  9. UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    Directory of Open Access Journals (Sweden)

    J. Para

    2013-04-01

    Full Text Available Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC, and optical characteristics including UV (ultraviolet radiation and PAR (photosynthetically active radiation diffuse attenuation (Kd, and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM as part of the MALINA field campaign (30 July to 27 August. Spectral absorption coefficients (aCDOM (350 nm (m−1 were significantly correlated to both diffuse attenuation coefficients (Kd in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of both UV and PAR solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. While the Mackenzie input is the main driver of CDOM dynamics in low salinity waters, locally, primary production can create significant increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that ∼16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. The discharges of DOC and its chromophoric subset (CDOM by the Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1–C3 were identified by fluorescence excitation/emission matrix spectroscopy (EEMS and parallel factor (PARAFAC analysis. Our results showed an aquatic dissolved organic matter (DOM component (C1, probably produced in the numerous lakes of the watershed, that co-dominated with a terrestrial humic-like component (C2 in the Mackenzie Delta Sector. This aquatic DOM could partially explain the high CDOM spectral slopes observed in the Beaufort Sea.

  10. UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    Science.gov (United States)

    Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

    2013-04-01

    Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV (ultraviolet) radiation and PAR (photosynthetically active radiation) diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of both UV and PAR solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. While the Mackenzie input is the main driver of CDOM dynamics in low salinity waters, locally, primary production can create significant increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that ∼16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. The discharges of DOC and its chromophoric subset (CDOM) by the Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence excitation/emission matrix spectroscopy (EEMS) and parallel factor (PARAFAC) analysis. Our results showed an aquatic dissolved organic matter (DOM) component (C1), probably produced in the numerous lakes of the watershed, that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta Sector. This aquatic DOM could partially explain the high CDOM spectral slopes observed in the Beaufort Sea.

  11. UV/PAR radiations and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    Science.gov (United States)

    Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

    2012-11-01

    Water masses from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV and PAR diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Even with relatively low mean daily solar radiation incident on the sea surface (0.12 ± 0.03, 8.46 ± 1.64 and 18.09 ± 4.20 kJ m-2 for UV-B (305 nm), UV-A (380 nm) and PAR, respectively), we report significant light penetration with 10% irradiance depths (Z10% (λ)) reaching 9.5 m for 340 nm (UV-A) radiation in the Eastern sector and 4.5 m in the Mackenzie River influenced area (Western sector). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of UV solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. Extrapolating CDOM to DOC relationships, we estimate that ~ 16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. DOC and CDOM discharges by the Mackenzie River during the MALINA Cruise are estimated as ~ 0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence Excitation/Emission Matrix Spectroscopy (EEMS) and PARAFAC analysis. Our results showed an in-situ biological component (C1) that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta sector, whereas the protein-like (C3) component dominated in the saltiest waters of the North East sector.

  12. Four cases of endophthalmitis after 25-gauge pars plana vitrectomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-08-01

    Full Text Available Tetsuya Mutoh, Koji Kadoya, Makoto ChikudaDepartment of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, JapanAbstract: We report our recent experience with four cases of endophthalmitis (one male, three females after 25-gauge pars plana vitrectomy (PPV. One was a case of persistent cystoid macular edema caused by branch retinal vein occlusion, whereas the remaining three were cases of epiretinal membrane. Preoperative antibiotics before the first PPV procedure were not administered in three of the four cases. Endophthalmitis occurred 2–4 days after the first procedure in all cases, for which ceftazidime 2.0 mg/0.1 mL and vancomycin 1.0 mg/0.1 mL were injected into the vitreous cavity. This was followed by emergent 20-gauge PPV and intraocular lens removal using an infusion fluid containing ceftazidime and vancomycin. After the second PPV procedure, progress was good in three cases while retinal detachment occurred in the remaining case one month after surgery; this case required a third PPV procedure. Final best-corrected visual acuity ranged from 20/100 to 20/25 for the four cases. Bacterial cultures were negative after the second PPV procedure in all cases. In conclusion, postoperative endophthalmitis occurred in four of 502 cases (0.80% that underwent 25-gauge PPV at our hospital. It is important to minimize the incidence of endophthalmitis after 25-gauge PPV.Keywords: 25-gauge pars plana vitrectomy, endophthalmitis, incidence

  13. Stress reactions involving the pars interarticularis in young athletes

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, D.W.; Wiltse, L.L.; Dingeman, R.D.; Hayes, M.

    A stress reaction involving the pars interarticularis of the lumbar spine was confirmed in seven young athletes with a positive technetium pyrophosphate bone scan. No pars defects were detectable on their lumbosacral roentgenograms, which included oblique views. The return to normal levels of radioactive uptake on repeat bone scans correlated closely with their clinical course. If the bony reaction is recognized early, it may heal at a subroentgenographic level and prevent the development of lumbar spondylolysis. These early lesions usually show unilateral increased uptake at one lumbar level on the bone scan and, initially, the athlete localizes the pain to the corresponding unilateral lumbar paraspinous area. The ''one-legged hyperextension test'' is positive on the ipsilateral side and aggravates the pain. Treatment consists of avoiding the aggravating activities and resting. The average time for return to pain-free competition was 7.3 months. These developing defects may be the source of considerable prolonged disability in the young athlete, particularly if undiagnosed and untreated.

  14. Stress reactions involving the pars interarticularis in young athletes

    International Nuclear Information System (INIS)

    Jackson, D.W.; Wiltse, L.L.; Dingeman, R.D.; Hayes, M.

    1981-01-01

    A stress reaction involving the pars interarticularis of the lumbar spine was confirmed in seven young athletes with a positive technetium pyrophosphate bone scan. No pars defects were detectable on their lumbosacral roentgenograms, which included oblique views. The return to normal levels of radioactive uptake on repeat bone scans correlated closely with their clinical course. If the bony reaction is recognized early, it may heal at a subroentgenographic level and prevent the development of lumbar spondylolysis. These early lesions usually show unilateral increased uptake at one lumbar level on the bone scan and, initially, the athlete localizes the pain to the corresponding unilateral lumbar paraspinous area. The ''one-legged hyperextension test'' is positive on the ipsilateral side and aggravates the pain. Treatment consists of avoiding the aggravating activities and resting. The average time for return to pain-free competition was 7.3 months. These developing defects may be the source of considerable prolonged disability in the young athlete, particularly if undiagnosed and untreated

  15. Structural design of intrinsically fluorescent oxysterols

    DEFF Research Database (Denmark)

    Nåbo, Lina J; Modzel, Maciej; Krishnan, Kathiresan

    2018-01-01

    Oxysterols are oxidized derivatives of cholesterol with many important biological functions. Trafficking of oxysterols in and between cells is not well studied, largely due to the lack of appropriate oxysterol analogs. Intrinsically fluorescent oxysterols present a new route towards direct...... observation of intracellular oxysterol trafficking by fluorescence microscopy. We characterize the fluorescence properties of the existing fluorescent 25-hydroxycholesterol analog 25-hydroxycholestatrienol, and propose a new probe with an extended conjugated system. The location of both probes inside...

  16. Réduction du risque d'infection par le VIH au Botswana - essais ...

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

    Au Botswana, ce sont les jeunes femmes qui sont le plus touchées par les nouvelles infections par le VIH. Le présent projet a pour but de réduire le nombre de nouveaux cas d'infection par le VIH, en particulier chez les femmes de 15 à 29 ans. Bien que l'on recense des cas de VIH/sida dans la plupart des régions du ...

  17. Plasmonic enhancement of ultraviolet fluorescence

    Science.gov (United States)

    Jiao, Xiaojin

    Plasmonics relates to the interaction between electromagnetic radiation and conduction electrons at metallic interfaces or in metallic nanostructures. Surface plasmons are collective electron oscillations at a metal surface, which can be manipulated by shape, texture and material composition. Plasmonic applications cover a broad spectrum from visible to near infrared, including biosensing, nanolithography, spectroscopy, optoelectronics, photovoltaics and so on. However, there remains a gap in this activity in the ultraviolet (UV, research. Motivating factors in the study of UV Plasmonics are the direct access to biomolecular resonances and native fluorescence, resonant Raman scattering interactions, and the potential for exerting control over photochemical reactions. This dissertation aims to fill in the gap of Plasmonics in the UV with efforts of design, fabrication and characterization of aluminium (Al) and magnesium (Mg) nanostructures for the application of label-free bimolecular detection via native UV fluorescence. The first contribution of this dissertation addresses the design of Al nanostructures in the context of UV fluorescence enhancement. A design method that combines analytical analysis with numerical simulation has been developed. Performance of three canonical plasmonic structures---the dipole antenna, bullseye nanoaperture and nanoaperture array---has been compared. The optimal geometrical parameters have been determined. A novel design of a compound bullseye structure has been proposed and numerically analyzed for the purpose of compensating for the large Stokes shift typical of UV fluorescence. Second, UV lifetime modification of diffusing molecules by Al nanoapertures has been experimentally demonstrated for the first time. Lifetime reductions of ~3.5x have been observed for the high quantum yield (QY) laser dye p-terphenyl in a 60 nm diameter aperture with 50 nm undercut. Furthermore, quantum-yield-dependence of lifetime reduction has been

  18. Demonstrating Fluorescence with Neon Paper and Plastic

    Science.gov (United States)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  19. PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity.

    Science.gov (United States)

    Fukushima, Henrique; Alves, Vanessa Tubero Euzebio; Carvalho, Verônica Franco de; Ambrósio, Lucas Macedo Batitucci; Eichler, Rosangela Aparecida Dos Santos; Carvalho, Maria Helena Catelli de; Saraiva, Luciana; Holzhausen, Marinella

    2017-01-26

    Recent studies investigating protease-activated receptor type 2 (PAR-2) suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF) of patients with moderate chronic periodontitis (MP). The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19) at baseline, and from MP patients (n = 19) and severe chronic periodontitis (SP) (n = 19) patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA) in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR). PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

  20. Total Internal Reflection Fluorescence Microscopy Imaging-Guided Confocal Single-Molecule Fluorescence Spectroscopy

    OpenAIRE

    Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter

    2013-01-01

    We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...

  1. Fluorescent scattering by molecules embedded in small particles

    International Nuclear Information System (INIS)

    1982-01-01

    Studies are reported in these areas: double resonance in fluorescent and Raman scattering; surface enhanced Raman scattering; fluorescence by molecules embedded in small particles; fluorescence by a liquid droplet; and fluorescence by conical pits in surfaces

  2. Fluorescence detection of dental calculus

    International Nuclear Information System (INIS)

    Gonchukov, S; Sukhinina, A; Vdovin, Yu; Biryukova, T

    2010-01-01

    This work is devoted to the optimization of fluorescence dental calculus diagnostics in optical spectrum. The optimal wavelengths for fluorescence excitation and registration are determined. Two spectral ranges 620 – 645 nm and 340 – 370 nm are the most convenient for supra- and subgingival calculus determination. The simple implementation of differential method free from the necessity of spectrometer using was investigated. Calculus detection reliability in the case of simple implementation is higher than in the case of spectra analysis at optimal wavelengths. The use of modulated excitation light and narrowband detection of informative signal allows us to decrease essentially its diagnostic intensity even in comparison with intensity of the low level laser dental therapy

  3. Sorting fluorescent nanocrystals with DNA

    Energy Technology Data Exchange (ETDEWEB)

    Gerion, Daniele; Parak, Wolfgang J.; Williams, Shara C.; Zanchet, Daniela; Micheel, Christine M.; Alivisatos, A. Paul

    2001-12-10

    Semiconductor nanocrystals with narrow and tunable fluorescence are covalently linked to oligonucleotides. These biocompounds retain the properties of both nanocrystals and DNA. Therefore, different sequences of DNA can be coded with nanocrystals and still preserve their ability to hybridize to their complements. We report the case where four different sequences of DNA are linked to four nanocrystal samples having different colors of emission in the range of 530-640 nm. When the DNA-nanocrystal conjugates are mixed together, it is possible to sort each type of nanoparticle using hybridization on a defined micrometer -size surface containing the complementary oligonucleotide. Detection of sorting requires only a single excitation source and an epifluorescence microscope. The possibility of directing fluorescent nanocrystals towards specific biological targets and detecting them, combined with their superior photo-stability compared to organic dyes, opens the way to improved biolabeling experiments, such as gene mapping on a nanometer scale or multicolor microarray analysis.

  4. Fluorescence spectroscopy for neoplasms control

    Science.gov (United States)

    Bratchenko, I. A.; Kristoforova, Yu. A.; Myakinin, O. O.; Artemyev, D. N.; Kozlov, S. V.; Moryatov, A. A.; Zakharov, V. P.

    2016-04-01

    Investigation of malignant skin tumors diagnosis was performed involving two setups for native tissues fluorescence control in visible and near infrared regions. Combined fluorescence analysis for skin malignant melanomas and basal cell carcinomas was performed. Autofluorescence spectra of normal skin and oncological pathologies stimulated by 457 nm and 785 nm lasers were registered for 74 skin tissue samples. Spectra of 10 melanomas and 27 basal cell carcinomas were registered ex vivo. Skin tumors analysis was made on the basis of autofluorescence spectra intensity and curvature for analysis of porphyrins, lipo-pigments, flavins and melanin. Separation of melanomas and basal cell carcinomas was performed on the basis of discriminant analysis. Overall accuracy of basal cell carcinomas and malignant melanomas separation in current study reached 86.5% with 70% sensitivity and 92.6% specificity.

  5. New Fluorescence Probes for Biomolecules

    Directory of Open Access Journals (Sweden)

    Katarzyna Jurek

    2015-07-01

    Full Text Available Steady state fluorescence measurements have been used for the investigation of interaction between the bovine serum albumin (BSA and fluorescence probes: 3-hydroxy-2,4- bis[(3-methyl-1,3-benzoxazol-2(3H-ylidenemethyl]cyclobut-2-en-1-one (SQ6, 3-hydroxy- 2,4-bis[(3-methyl-1,3-benzothiazol-2(3H-ylidenemethyl]cyclobut-2-en-1-one (SQ7 and 3-hydroxy-2,4-bis[(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidenemethyl]cyclobut-2-en-1-one (SQ8. The binding constant between bovine serum albumin and squarine dyes has been determined by using both the Benesi-Hildebrand and Stern-Volmer equations. The negative value of free energy change indicates the existence of a spontaneous complexation process of BSA with squarine dyes.

  6. Multi Spectral Fluorescence Imager (MSFI)

    Science.gov (United States)

    Caron, Allison

    2016-01-01

    Genetic transformation with in vivo reporter genes for fluorescent proteins can be performed on a variety of organisms to address fundamental biological questions. Model organisms that may utilize an ISS imager include unicellular organisms (Saccharomyces cerevisiae), plants (Arabidopsis thaliana), and invertebrates (Caenorhabditis elegans). The multispectral fluorescence imager (MSFI) will have the capability to accommodate 10 cm x 10 cm Petri plates, various sized multi-well culture plates, and other custom culture containers. Features will include programmable temperature and light cycles, ethylene scrubbing (less than 25 ppb), CO2 control (between 400 ppm and ISS-ambient levels in units of 100 ppm) and sufficient airflow to prevent condensation that would interfere with imaging.

  7. X-ray fluorescence holography.

    Science.gov (United States)

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Hu, Wen; Matsushita, Tomohiro

    2012-03-07

    X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. Because of this feature, XFH is expected to be used for medium-range local structural analysis, which cannot be performed by x-ray diffraction or x-ray absorption fine structure analysis. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy.

  8. X-ray fluorescence holography

    International Nuclear Information System (INIS)

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Hu Wen; Matsushita, Tomohiro

    2012-01-01

    X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. Because of this feature, XFH is expected to be used for medium-range local structural analysis, which cannot be performed by x-ray diffraction or x-ray absorption fine structure analysis. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy. (topical review)

  9. Un « gouvernement des journalistes par le Pouvoir politique » par défaut ?

    Directory of Open Access Journals (Sweden)

    Matthieu Lardeau

    2013-12-01

    Full Text Available Cet article présente les interactions de deux mouvements concomitants apparusprincipalement dans les décennies 1950 à 1970 dans le champ de la presse française : d’un côté les initiatives – consécutives à la démarche pionnière, en 1951, de création de la première Société des journalistes (SDJ au sein du Monde – menées par les journalistes de rédactions de quotidiens pour créer des SDJ dont la destination peut aller jusqu’à gouverner les journaux; de l’autre côté, les « réponses » apportées par les Pouvoirs politique et public pour contenir ces initiatives visant à étendre le pouvoir des journalistes dans la gestion et la gouvernance de leurs journaux. Cette étude exploratoire repose principalement sur l’analyse de deux types de littérature, souvent déconsidérés ou négligés par le champ académique, en dépit de leur grande richesse : (1 la littérature professionnelle, ayant pour principaux auteurs les journalistes et managers de presse (Périer Daville, Boegner, Pigasse, etc., florissante depuis 1944 et singulièrement durant les décennies 1960 et 1970 ; (2 la littérature grise constituée notamment par des rapports publics rédigés par des institutions comme les services du Premier ministre (commissions Lindon de 1970 et Serisé de 1972, le Conseil économique et social, etc. Nos principaux résultats montrent que les propositions ou actions menées par les journalistes (1 restent le plus souvent inexploitées in concreto par les journalistes eux-mêmes; (2 entrent le plus souvent en opposition avec les politiques de nouveaux actionnaires ou directions de journaux et avec les projets des autorités politiques et publiques qui cherchent à encadrer l’autonomie de la profession journalistique pour mieux gouverner celle-ci ; (3 combien in fine les représentants des différents acteurs impliqués s’accordent pour contenir l’émergence d’un « gouvernement des journalistes » par les

  10. Fluorescence lifetime imaging of skin cancer

    Science.gov (United States)

    Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

    2011-03-01

    Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

  11. Baixas temperaturas sobre a fluorescência da clorofila a em plantas de diferentes híbridos de canola

    Directory of Open Access Journals (Sweden)

    Anelise Tessari Perboni

    2015-02-01

    Full Text Available O objetivo do trabalho foi estudar os efeitos de baixas temperaturas sobre o aparato fotossintético de híbridos de canola. Plantas de canola foram cultivadas em casa de vegetação e, 50 dias após a semeadura, acondicionadas em câmara de crescimento com ausência de luz, onde foram submetidas a temperaturas de 0 ou 4oC pelo período de 1 ou 4 horas. Avaliou-se a cinética de emissão da fluorescência da clorofila a. Os híbridos apresentaram o mesmo comportamento em relação à fluorescência da clorofila em resposta ao estresse. Os parâmetros da fluorescência foram amplamente afetados em todos os tratamentos e a análise da cinética revelou efeitos da temperatura, principalmente no passo J, que representa o acúmulo de plastoquinona reduzida e na fase I-P, que reflete a redução dos aceptores de elétrons finais do lado aceptor do fotossistema I. Conclui-se que os parâmetros mais responsivos às condições impostas pelo frio são os que descrevem o grau de reoxidação do aceptor final de elétrons do fotossistema II e a atividade do fotossistema I

  12. The polarity protein Par6 is coupled to the microtubule network during molluscan early embryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Taihei [Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Shimizu, Miho [Kuroda Chiromorphology Team, ERATO-SORST, JST, Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Kuroda, Reiko, E-mail: ckuroda@mail.ecc.u-tokyo.ac.jp [Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kuroda Chiromorphology Team, ERATO-SORST, JST, Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2011-01-07

    Research highlights: {yields} The cDNAs encoding Par6 and aPKC homologues were cloned from the snail Lymnaea stagnalis. {yields} L. stagnalis Par6 directly interacts with tubulin and microtubules and localizes to the microtubule cytoskeleton during the early embryogenesis. {yields} Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of body handedness. -- Abstract: Cell polarity, which directs the orientation of asymmetric cell division and segregation of fate determinants, is a fundamental feature of development and differentiation. Regulators of polarity have been extensively studied, and the critical importance of the Par (partitioning-defective) complex as the polarity machinery is now recognized in a wide range of eukaryotic systems. The Par polarity module is evolutionarily conserved, but its mechanism and cooperating factors vary among different systems. Here we describe the cloning and characterization of a pond snail Lymnaea stagnalis homologue of partitioning-defective 6 (Lspar6). The protein product LsPar6 shows high affinity for microtubules and localizes to the mitotic apparatus during embryonic cell division. In vitro assays revealed direct binding of LsPar6 to tubulin and microtubules, which is the first evidence of the direct interaction between the two proteins. The interaction is mediated by two distinct regions of LsPar6 both located in the N-terminal half. Atypical PKC, a functional partner of Par6, was also found to localize to the mitotic spindle. These results suggest that the L. stagnalis Par complex employs the microtubule network in cell polarity processes during the early embryogenesis. Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of handedness.

  13. The polarity protein Par6 is coupled to the microtubule network during molluscan early embryogenesis

    International Nuclear Information System (INIS)

    Homma, Taihei; Shimizu, Miho; Kuroda, Reiko

    2011-01-01

    Research highlights: → The cDNAs encoding Par6 and aPKC homologues were cloned from the snail Lymnaea stagnalis. → L. stagnalis Par6 directly interacts with tubulin and microtubules and localizes to the microtubule cytoskeleton during the early embryogenesis. → Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of body handedness. -- Abstract: Cell polarity, which directs the orientation of asymmetric cell division and segregation of fate determinants, is a fundamental feature of development and differentiation. Regulators of polarity have been extensively studied, and the critical importance of the Par (partitioning-defective) complex as the polarity machinery is now recognized in a wide range of eukaryotic systems. The Par polarity module is evolutionarily conserved, but its mechanism and cooperating factors vary among different systems. Here we describe the cloning and characterization of a pond snail Lymnaea stagnalis homologue of partitioning-defective 6 (Lspar6). The protein product LsPar6 shows high affinity for microtubules and localizes to the mitotic apparatus during embryonic cell division. In vitro assays revealed direct binding of LsPar6 to tubulin and microtubules, which is the first evidence of the direct interaction between the two proteins. The interaction is mediated by two distinct regions of LsPar6 both located in the N-terminal half. Atypical PKC, a functional partner of Par6, was also found to localize to the mitotic spindle. These results suggest that the L. stagnalis Par complex employs the microtubule network in cell polarity processes during the early embryogenesis. Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of handedness.

  14. Paternal age related schizophrenia (PARS): Latent subgroups detected by k-means clustering analysis.

    Science.gov (United States)

    Lee, Hyejoo; Malaspina, Dolores; Ahn, Hongshik; Perrin, Mary; Opler, Mark G; Kleinhaus, Karine; Harlap, Susan; Goetz, Raymond; Antonius, Daniel

    2011-05-01

    Paternal age related schizophrenia (PARS) has been proposed as a subgroup of schizophrenia with distinct etiology, pathophysiology and symptoms. This study uses a k-means clustering analysis approach to generate hypotheses about differences between PARS and other cases of schizophrenia. We studied PARS (operationally defined as not having any family history of schizophrenia among first and second-degree relatives and fathers' age at birth ≥ 35 years) in a series of schizophrenia cases recruited from a research unit. Data were available on demographic variables, symptoms (Positive and Negative Syndrome Scale; PANSS), cognitive tests (Wechsler Adult Intelligence Scale-Revised; WAIS-R) and olfaction (University of Pennsylvania Smell Identification Test; UPSIT). We conducted a series of k-means clustering analyses to identify clusters of cases containing high concentrations of PARS. Two analyses generated clusters with high concentrations of PARS cases. The first analysis (N=136; PARS=34) revealed a cluster containing 83% PARS cases, in which the patients showed a significant discrepancy between verbal and performance intelligence. The mean paternal and maternal ages were 41 and 33, respectively. The second analysis (N=123; PARS=30) revealed a cluster containing 71% PARS cases, of which 93% were females; the mean age of onset of psychosis, at 17.2, was significantly early. These results strengthen the evidence that PARS cases differ from other patients with schizophrenia. Hypothesis-generating findings suggest that features of PARS may include a discrepancy between verbal and performance intelligence, and in females, an early age of onset. These findings provide a rationale for separating these phenotypes from others in future clinical, genetic and pathophysiologic studies of schizophrenia and in considering responses to treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. An operational fluorescence system for crop assessment

    Science.gov (United States)

    Belzile, Charles; Belanger, Marie-Christine; Viau, Alain A.; Chamberland, Martin; Roy, Simon

    2004-03-01

    The development of precision farming requires new tools for plant nutritional stress monitoring. An operational fluorescence system has been designed for vegetation status mapping and stress detection at plant and field scale. The instrument gives relative values of fluorescence at different wavelengths induced by the two-excitation sources. Lightinduced fluorescence has demonstrated successful crop health monitoring and plant nutritional stress detection capabilities. The spectral response of the plants has first been measured with an hyperspectral imager using laser-induced fluorescence. A tabletop imaging fluorometer based on flash lamp technology has also been designed to study the spatial distribution of fluorescence on plant leaves. For field based non-imaging system, LED technology is used as light source to induce fluorescence of the plant. The operational fluorescence system is based on ultraviolet and blue LED to induce fluorescence. Four narrow fluorescence bands centered on 440, 520, 690 and 740nm are detected. The instrument design includes a modular approach for light source and detector. It can accommodate as many as four different light sources and six bands of fluorescence detection. As part of the design for field application, the instrument is compatible with a mobile platform equipped with a GPS and data acquisition system. The current system developed by Telops/GAAP is configured for potato crops fluorescence measurement but can easily be adapted for other crops. This new instrument offers an effective and affordable solution for precision farming.

  16. Electron microscope study of vacancy clusters produced by quenching in magnesium; Etude par microscopie electronique des amas de lacunes crees par trempe dans le magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Levy, V; Espinasse, J; Mairy, C; Hillairet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    Vacancy clustering in quenched magnesium has been studied by transmission electron microscopy. The nature of the vacancy loops observed, seems to depend essentially on the impurity content of the metal; this effect can be attributed to a variation of the stacking fault energy of magnesium due to impurities. (authors) [French] On a etudie par microscopie electronique en transmission les defauts crees par trempe dans le magnesium. Un effet considerable des impuretes du metal sur la nature des boucles obtenues par condensation de lacunes a ete mis en evidence; cet effet semble s'expliquer de facon satisfaisante par un abaissement de l'energie de faute d'empilement du magnesium du aux impuretes. (auteur)

  17. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  18. Cancro em mogno africano no estado do Pará

    Directory of Open Access Journals (Sweden)

    Célia Regina Tremacoldi

    2013-06-01

    Full Text Available Sintomas de cancro foram observados em plantios de mogno africano, no município de Dom Eliseu, Pará. Os fungos associados aos tecidos sintomáticos foram identificados como Lasiodiplodia theobromae e Fusarium subglutinans. Culturas puras desses fungos foram testadas quanto à patogenicidade em mudas de mogno africano sadias. Apenas L. theobromae produziu cancro, por meio de inoculação por ferimento e alta umidade. A confirmação de L. theobromae como agente causal do cancro ocorreu após o reisolamento do fungo a partir das plantas inoculadas em casa de vegetação, concluindo a primeira verificação do postulado de Koch para esse patossistema.

  19. IMPROVEMENT OF PRODUCTION PLANNING IN COMPANY PARS KOMPONENTY

    Directory of Open Access Journals (Sweden)

    René Klega

    2014-03-01

    Full Text Available The article analyzes the current status of production planning in company Pars Komponenty s.r.o., proposes a new method of planning based on application of the principle of MRP. It is a discrete type of production with high complexity of BOM and MTO (Make-to-Order and ETO (Engineering-to-Order from the point of decoupling point. The original planning system plans according to production capacity backward without collisions, but for a given type of production does not work in practice. Planning system was analyzed and the main problems were identified, which were high work in progress and material stocks. This article target is to propose a new planining system based on the inclusion of time reserves of purchased material items. New planning system was tested in practise with benefit in reducing both the material inventory and work in progress.

  20. Pierre Vilar Frontinhan 1906 - París 2003

    Directory of Open Access Journals (Sweden)

    Pablo Rodríguez

    2003-01-01

    Full Text Available En el pasado mes de agosto falleció en París el historiador y maestro de tantas generaciones Pierre Vilar. Aunque había mantenido una intensa actividad de reflexión sobre los sucesos contemporáneos, ésta se vio afectada en 1991 luego que una grave enfermedad le negó la visión. Fue entonces cuando decidió con la ayuda de Rosa Congost escribir sus reflexiones y recuerdos, especie de memoria de juventud. Pensar Históricamente (Barcelona: Editorial Crítica, 1997, el libro que reúne estos ejercicios, es una obra de sumo interés para conocer la infancia, adolescencia y juventud de este connotado historiador.

  1. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  2. Determination of tritium by counting; Dosage du tritium par comptage

    Energy Technology Data Exchange (ETDEWEB)

    Schott, R; Froment, G; Pinson, J; Genty, C [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1968-07-01

    Ionisation chamber assay of tritium in any gaseous mixture is a simple, fast and accurate method. We used the method of relative determination by comparison to a standard rather than the method of absolute assay in which case the constants are known with too little accuracy. The efficiency of the chamber was studied in connection to the pressure inside the chamber and its total volume. The calibration is linear in the range we are taking into account (1 to 80 millicuries). The reproducibility of the method is good: 13 runs gave a coefficient of variation of 1.6 per cent. The relative accuracy was found equal to {+-} 1.3 per cent. To end the paper, we describe in detail the apparatus and the ways of proceedings. (authors) [French] Le comptage du tritium par chambre d'ionisation est une methode simple, rapide et precise pour determiner la teneur en tritium d'un melange gazeux quelconque. Nous avons prefere utiliser la methode de determination relative par rapport a un etalon car, dans le cas d'une determination absolue, les constantes sont connues avec une trop grande incertitude. L'efficacite de la chambre a ete etudiee en fonction de la variation de la pression d'argon a l'interieur de la chambre et du volume total, de cette derniere. L'etalonnage s'est revele lineaire dans le domaine de mesures qui nous interessaient (1 a 80 millicuries). La reproductibillte de la methode est tres bonne, le coefficient de variation pour une serie de 13 essais etant de 1,6 pour cent, quant a la precision relative, elle a ete evaluee a {+-} 1,3 pour cent. Pour terminer, nous donnons une description detaillee de l'appareillage utilise et du mode operatoire suivi. (auteurs)

  3. Clinical outcomes of pars plicata anterior vitrectomy: 2-year results

    Directory of Open Access Journals (Sweden)

    Priya Narang

    2015-01-01

    Full Text Available Purpose: To demonstrate the safety and outcome of a surgical approach that uses pars plicata site for anterior vitrectomy during phacoemulsification procedure complicated by posterior capsule rupture and residual cortical matter. Design: Single center, retrospective, interventional, noncomparative study. Materials and Methods: Medical records of a consecutive series of 35 eyes of 35 patients who underwent pars plicata anterior vitrectomy (PPAV were reviewed. The main outcome measures were corrected and uncorrected distance visual acuity (CDVA, UDVA, early and late postoperative complications and intraocular pressure (IOP. Ultrasound biomicroscopic (UBM evaluation of sclerotomy site and spectral domain optical coherence tomography analysis for central macular thickness (CMT was performed. The final visual outcome at 2 years was evaluated. Results: At 2 years follow-up, the mean postoperative UDVA (logarithm of the minimum angle of resolution [logMAR] and CDVA (logMAR was 0.49 ± 0.26 and 0.19 ± 0.14, respectively. There was no significant change in the IOP (P = 0.061 and the mean CMT at 2 years was 192.5 ± 5.54 mm. The postoperative UBM image of the sclerotomy site at 8 weeks demonstrated a clear wound without any vitreous adhesion or incarceration. Intraoperative hyphema was seen in 1 (2.8% case and postoperative uveitis was seen in 2 (5.7% cases, which resolved with medications. No case of an iatrogenic retinal break or retinal detachment was reported. Conclusions: PPAV enables a closed chamber approach, allows thorough cleanup of vitreous in the pupillary plane and anterior chamber and affords better access to the subincisional and retropupillary cortical remnant with a significant visual outcome and an acceptable complication rate.

  4. Urokinase-type plasminogen activator receptor (uPAR) as a promising new imaging target

    DEFF Research Database (Denmark)

    Persson, Morten; Kjaer, Andreas

    2013-01-01

    modalities such as optical imaging, magnetic resonance imaging, single photon emission computer tomography (SPECT) and positron emission topography (PET). In this review, we will discuss recent advances in the development of uPAR-targeted imaging ligands according to imaging modality. In addition, we...... will discuss the potential future clinical application for uPAR imaging as a new imaging biomarker....

  5. Pars plana vitrectomy for disturbing primary vitreous floaters: clinical outcome and patient satisfaction

    NARCIS (Netherlands)

    Nie, K.F. de; Crama, N.; Tilanus, M.A.D.; Klevering, B.J.; Boon, C.J.F.

    2013-01-01

    BACKGROUND: Primary vitreous floaters can be highly bothersome in some patients. In the case of persistently bothersome floaters, pars plana vitrectomy may be the most effective treatment. The aim of this study is to evaluate the incidence of complications, and patient satisfaction, after pars plana

  6. Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae.

    Science.gov (United States)

    Enberg, Sara; Piiparinen, Jonna; Majaneva, Markus; Vähätalo, Anssi V; Autio, Riitta; Rintala, Janne-Markus

    2015-10-01

    The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly Scrippsiella hangoei, Biecheleria baltica and Gymnodinium corollarium) showed UV sensitivity in the top 5-cm layer, whereas Heterocapsa arctica ssp. frigida and green algae showed sensitivity to both PAR and UVR. The photosynthetic activity was highest in the top 5-cm layer of the PAR treatment, where the biomass of the pennate diatom Nitzschia frigida increased, indicating the UV sensitivity of this species. This study shows that UVR is one of the controlling factors of algal communities in Baltic Sea ice, and that increased availability of PAR together with UVR exclusion can cause changes in algal biomass, photosynthetic activity and community composition. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Spectral variations of UV-A and PAR solar radiation in estuarine waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Talaulikar, M.; Suresh, T.; Silveira, N.; Desa, E.; Matondkar, S; Lotlikar, A

    radiation (400 to 700 nm), PAR and ultraviolet radiation in the range 350-400 nm (UV-A) are presented here. The mean PAR values at the surface were 327 W/m sup(2) and reduced to 84 W/m sup(2) at first optical depth, Z sub(90) (m) in water. The first optical...

  8. Narrative Identities and the Plebiscite in Pará: An Analysis of the Front Pages for O Liberal and Diário do Pará

    Directory of Open Access Journals (Sweden)

    Alda Cristina Silva da Costa

    2017-05-01

    Full Text Available On December 11, 2011, a plebiscite was held in Pará proposing to create two separatist states, Carajás and Tapajós, out of the state of Pará. The public voted against both projects. This article analyzes the narrative identities found on the front pages of O Liberal and Diário do Pará newspapers about the plebiscite in Pará. Depth Hermeneutics (DH, as proposed by Thompson (2011, was used as the methodological reference. DH emphasizes the object of analysis as a meaningful symbolic construction requiring interpretation. Narrative analysis, as proposed by Motta (2007, was the main research technique used to highlight the movement of construction of journalistic (discursive characters. The narrative identities built by the two newspapers showed that both were against the creation of the new states, but for very different reasons. The flag of Pará was the main object used to induce the idea of unity. Em 11 de dezembro de 2011, o plebiscito no Pará propôs a criação dos estados de Carajás e de Tapajós a partir da divisão do estado do Pará. O resultado da consulta pública foi negativo aos dois projetos. O artigo analisa as identidades narrativas constituídas pelas primeiras páginas dos jornais O Liberal e Diário do Pará sobre o plebiscito no Pará. Utilizou-se como referencial metodológico a Hermenêutica em Profundidade (HP, proposta por Thompson (2011. A HP evidencia o fato de que o objeto de análise é uma construção simbólica significativa, que exige uma interpretação. Como principal técnica de pesquisa, a análise narrativa, proposta por Motta (2007, com ênfase no movimento de construção de personagens jornalísticas (discursivas. As identidades narrativas construídas pelos dois jornais indicaram que ambos eram contrários à criação dos novos estados, porém por motivos divergentes. A bandeira do Pará foi o principal elemento utilizado para evocar a ideia de unidade. En 11 de diciembre de 2011, el plebiscito en

  9. The urokinase receptor (uPAR) and the uPAR-associated protein (uPARAP/Endo180)

    DEFF Research Database (Denmark)

    Behrendt, Niels

    2004-01-01

    The breakdown of the barriers formed by extracellular matrix proteins is a pre-requisite for all processes of tissue remodeling. Matrix degradation reactions take part in specific physiological events in the healthy organism but also represent a crucial step in cancer invasion. These degradation...... on the surface of various cell types that serves to bind the urokinase plasminogen activator and localize the activation reactions in the proteolytic cascade system of plasminogen activation. uPARAP is an integral membrane protein with a pronounced role in the internalization of collagen for intracellular...... degradation. Both receptors have additional functions that are currently being unraveled. The present discussion of uPAR and uPARAP is centered on their protein structure and molecular and cellular function....

  10. Effect of simvastatin and ezetimibe on suPAR levels and outcomes

    DEFF Research Database (Denmark)

    Hodges, Gethin W; Bang, Casper N; Forman, Julie L

    2018-01-01

    -lowering therapy also lowers suPAR levels is unknown. METHODS: We investigated whether treatment with Simvastatin 40 mg and Ezetimibe 10 mg lowered plasma suPAR levels in 1838 patients with mild-moderate, asymptomatic aortic stenosis, included in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, using...... and Ezetimibe treatment impeded the progression of the time-related increase in plasma suPAR levels. Year-1 suPAR was associated with all-cause mortality, MCE, and AVE irrespective of baseline levels (SEAS study: NCT00092677)....... cardiovascular events (MCE) composed of ischemic cardiovascular events (ICE) and aortic valve related events (AVE). RESULTS: After 4.3 years of follow-up, suPAR levels had increased by 9.2% (95% confidence interval [CI]: 7.0%-11.5%) in the placebo group, but only by 4.1% (1.9%-6.2%) in the group with lipid...

  11. Brulure par Plaque de Bistouri Electrique: a Propos de Quatre Cas

    Science.gov (United States)

    Khales, A.; Achbouk, A.; Belmir, R.; Cherkab, L.; Ennouhi, M.A.; Ababou, K.; Ihrai, H.

    2010-01-01

    Summary La brûlure par plaque de bistouri électrique est un accident rare mais grave par la profondeur de la lésion et par sa localisation, surtout quand qu’elle survient dans un contexte chirurgical dont le vécu reste difficile de la part du malade et du chirurgien. Cette brûlure bien que imprévisible reste grave par la profondeur et la localisation de la brûlure et par sa survenue dans un contexte opératoire, chez des patients malades. La prise en charge de la brûlure doit se faire en milieu spécialisé. La prévention reste le seul moyen d’éviter ce type d’accident. PMID:21991216

  12. Evaluation des bassins par modélisation intégrée en deux dimensions des transferts techniques, de l'écoulement des fluides, de la genèse et de la migration des hydrocarbures Basin Evaluation by Integrated Two-Dimensional Modeling of Heat Transfer, Fluid Flow, Hydrocarbon Generation, and Migration

    Directory of Open Access Journals (Sweden)

    Chenet P. Y.

    2006-11-01

    Full Text Available Le modèle de bassin exposé dans cet article décrit les phénomènes physiques et chimiques qui contrôlent la formation d'accumulations commerciales, dans le cadre évolutif d'un bassin sédimentaire affecté par la subsidence : transfert de chaleur, compaction et écoulement de l'eau, génèse des hydrocarbures, migration diphasique de l'eau et des hydrocarbures. Le modèle tient compte des variations de conductivité et des phénomènes thermiques transitoires pour reconstituer les paléo-températures. Des validations quantitatives de la reconstitution des paléo-températures et du modèle cinétique de formation des hydrocarbures peuvent être obtenues par comparaison avec les températures actuelles et les données géochimiques. Les écoulements et les surpressions induits par la compaction sont décrits en couplant une loi de compaction avec la loi de Darcy, classique pour les écoulements de l'eau, en ajoutant un critère de fracturation hydraulique naturelle. Ceci permet de modéliser les pressions anormales dans des séquences deltaïques récentes (delta de la Mahakam, comme dans des bassins liés à des rifts anciens (mer du Nord. Une adaptation de la loi de Darcy aux écoulements diphasiques permet de reproduire la migration primaire et la migration secondaire. En particulier, le modèle permet d'étudier le rôle des pressions anormales et l'influence des failles sur la migration et le piégeage. Nos résultats confirment que les modèles de bassins peuvent contribuer à synthétiser les données géologiques, géophysiques et géochimiques dans un schéma cohérent. En précisant l'évaluation pétrolière, ces modèles constituent une des principales voies pour améliorer l'efficacité de l'exploration. The basin model discussed in this paper describes the physical and chemical phenomena that control the formation of commercial accumulations of hydrocarbons in the moving framework of a subsiding sedimentary basin : heat

  13. Fluorescent nanoparticles for intracellular sensing: A review

    International Nuclear Information System (INIS)

    Ruedas-Rama, Maria J.; Walters, Jamie D.; Orte, Angel; Hall, Elizabeth A.H.

    2012-01-01

    Highlights: ► Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. ► Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. ► Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  14. Fluorescent nanoparticles for intracellular sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ruedas-Rama, Maria J., E-mail: mjruedas@ugr.esmailto [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Walters, Jamie D. [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, UK CB2 1QT (United Kingdom); Orte, Angel [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Hall, Elizabeth A.H., E-mail: lisa.hall@biotech.cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT (United Kingdom)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. Black-Right-Pointing-Pointer Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. Black-Right-Pointing-Pointer Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  15. Three-dimensional fluorescence lifetime tomography

    International Nuclear Information System (INIS)

    Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.

    2005-01-01

    Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores

  16. Multispectral open-air intraoperative fluorescence imaging.

    Science.gov (United States)

    Behrooz, Ali; Waterman, Peter; Vasquez, Kristine O; Meganck, Jeff; Peterson, Jeffrey D; Faqir, Ilias; Kempner, Joshua

    2017-08-01

    Intraoperative fluorescence imaging informs decisions regarding surgical margins by detecting and localizing signals from fluorescent reporters, labeling targets such as malignant tissues. This guidance reduces the likelihood of undetected malignant tissue remaining after resection, eliminating the need for additional treatment or surgery. The primary challenges in performing open-air intraoperative fluorescence imaging come from the weak intensity of the fluorescence signal in the presence of strong surgical and ambient illumination, and the auto-fluorescence of non-target components, such as tissue, especially in the visible spectral window (400-650 nm). In this work, a multispectral open-air fluorescence imaging system is presented for translational image-guided intraoperative applications, which overcomes these challenges. The system is capable of imaging weak fluorescence signals with nanomolar sensitivity in the presence of surgical illumination. This is done using synchronized fluorescence excitation and image acquisition with real-time background subtraction. Additionally, the system uses a liquid crystal tunable filter for acquisition of multispectral images that are used to spectrally unmix target fluorescence from non-target auto-fluorescence. Results are validated by preclinical studies on murine models and translational canine oncology models.

  17. Red and Green Fluorescence from Oral Biofilms.

    Science.gov (United States)

    Volgenant, Catherine M C; Hoogenkamp, Michel A; Krom, Bastiaan P; Janus, Marleen M; Ten Cate, Jacob M; de Soet, Johannes J; Crielaard, Wim; van der Veen, Monique H

    2016-01-01

    Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation) as compared to the sucrose grown biofilms (cariogenic simulation). Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red) were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  18. Red and Green Fluorescence from Oral Biofilms.

    Directory of Open Access Journals (Sweden)

    Catherine M C Volgenant

    Full Text Available Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation as compared to the sucrose grown biofilms (cariogenic simulation. Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  19. MODIS-derived daily PAR simulation from cloud-free images and its validation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liangfu; Gu, Xingfa; Tian, Guoliang [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); The Center for National Spaceborne Demonstration, Beijing 100101 (China); Gao, Yanhua [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Yang, Lei [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Jilin University, Changchun 130026 (China); Liu, Qinhuo [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China)

    2008-06-15

    In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan's model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the gas mixture, absorption by ozone, the gas mixture and water vapor, and scattering and absorption by aerosols. The diffuse irradiance is scattered out of the direct beam and towards the surface. The multiple ground-air interactions have been taken into account in the diffuse irradiance model. The parameters needed in this model are atmospheric water vapor content, aerosol optical thickness and spectral albedo ranging from 400 nm to 700 nm. They are all retrieved from MODIS data. Then, the instantaneous photosynthetically available radiation (IPAR) is integrated by using a weighted sum at each of the visible MODIS wavebands. Finally, a daily PAR is derived by integration of IPAR. In order to validate the MODIS-derived PAR model, we compared the field PAR measurements in 2003 and 2004 against the simulated PAR. The measurements were made at the Qianyanzhou ecological experimental station, Chinese Ecosystem Research Network. A total of 54 days of cloud-free MODIS L1B level images were used for the PAR simulation. Our results show that the simulated PAR is consistent with field measurements, where the correlation coefficient of linear regression between calculated PAR and measured PAR is 0.93396. However, there were some uncertainties in the comparison of 1 km pixel PAR with the tower flux stand measurement. (author)

  20. Fluorescence imaging spectrometer optical design

    Science.gov (United States)

    Taiti, A.; Coppo, P.; Battistelli, E.

    2015-09-01

    The optical design of the FLuORescence Imaging Spectrometer (FLORIS) studied for the Fluorescence Explorer (FLEX) mission is discussed. FLEX is a candidate for the ESA's 8th Earth Explorer opportunity mission. FLORIS is a pushbroom hyperspectral imager foreseen to be embarked on board of a medium size satellite, flying in tandem with Sentinel-3 in a Sun synchronous orbit at a height of about 815 km. FLORIS will observe the vegetation fluorescence and reflectance within a spectral range between 500 and 780 nm. Multi-frames acquisitions on matrix detectors during the satellite movement will allow the production of 2D Earth scene images in two different spectral channels, called HR and LR with spectral resolution of 0.3 and 2 nm respectively. A common fore optics is foreseen to enhance by design the spatial co-registration between the two spectral channels, which have the same ground spatial sampling (300 m) and swath (150 km). An overlapped spectral range between the two channels is also introduced to simplify the spectral coregistration. A compact opto-mechanical solution with all spherical and plane optical elements is proposed, and the most significant design rationales are described. The instrument optical architecture foresees a dual Babinet scrambler, a dioptric telescope and two grating spectrometers (HR and LR), each consisting of a modified Offner configuration. The developed design is robust, stable vs temperature, easy to align, showing very high optical quality along the whole field of view. The system gives also excellent correction for transverse chromatic aberration and distortions (keystone and smile).

  1. DNA nanotechnology and fluorescence applications.

    Science.gov (United States)

    Schlichthaerle, Thomas; Strauss, Maximilian T; Schueder, Florian; Woehrstein, Johannes B; Jungmann, Ralf

    2016-06-01

    Structural DNA nanotechnology allow researchers to use the unique molecular recognition properties of DNA strands to construct nanoscale objects with almost arbitrary complexity in two and three dimensions. Abstracted as molecular breadboards, DNA nanostructures enable nanometer-precise placement of guest molecules such as proteins, fluorophores, or nanoparticles. These assemblies can be used to study biological phenomena with unprecedented control over number, spacing, and molecular identity. Here, we give a general introduction to structural DNA nanotechnology and more specifically discuss applications of DNA nanostructures in the field of fluorescence and plasmonics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Urine suPAR levels compared with plasma suPAR levels as predictors of post-consultation mortality risk among individuals assumed to be TB-negative: a prospective cohort study

    DEFF Research Database (Denmark)

    Rabna, Paulo; Andersen, Andreas; Wejse, Christian

    2010-01-01

    -suPAR was measured using a commercial ELISA (suPARnostic®). We found that U-suPAR carried significant prognostic information on mortality for HIV-infected subjects with an area under the ROC curve of 0.75. For HIV-negative individuals, little or no prognostic effect was observed. However, in both HIV positives...... and negatives, the predictive effect of U-suPAR was found to be inferior to that of P-suPAR....

  3. Detection of Counterfeit Tequila by Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    José Manuel de la Rosa Vázquez

    2015-01-01

    Full Text Available An ultraviolet (UV light induced fluorescence study to discriminate fake tequila from genuine ones is presented. A portable homemade system based on four light emitting diodes (LEDs from 255 to 405 nm and a miniature spectrometer was used. It has been shown that unlike fake and silver tequila, which produce weak fluorescence signal, genuine mixed, rested, and aged tequilas show high fluorescence emission in the range from 400 to 750 nm. The fluorescence intensity grows with aging in 100% agave tequila. Such fluorescence differences can even be observed with naked eyes. The presented results demonstrate that the fluorescence measurement could be a good method to detect counterfeit tequila.

  4. Confocal fluorescence techniques in industrial application

    Science.gov (United States)

    Eggeling, Christian; Gall, Karsten; Palo, Kaupo; Kask, Peet; Brand, Leif

    2003-06-01

    The FCS+plus family of evaluation tools for confocal fluorescence spectroscopy, which was developed during recent years, offers a comprehensive view to a series of fluorescence properties. Originating in fluorescence correlation spectroscopy (FCS) and using similar experimental equipment, a system of signal processing methods such as fluorescence intensity distribution analysis (FIDA) was created to analyze in detail the fluctuation behavior of fluorescent particles within a small area of detection. Giving simultaneous access to molecular parameters like concentration, translational and rotational diffusion, molecular brightness, and multicolor coincidence, this portfolio was enhanced by more traditional techniques of fluorescence lifetime as well as time-resolved anisotropy determination. The cornerstones of the FCS+plus methodology will be shortly described. The inhibition of a phosphatase enzyme activity gives a comprehensive industrial application that demonstrates FCS+plus' versatility and its potential for pharmaceutical drug discovery.

  5. Fluorescence fluctuation spectroscopy (FFS), part A

    CERN Document Server

    Tetin, Sergey

    2013-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial by containing quality chapters authored by leaders in the field. This volume covers Fluorescence Fluctuation SpectroscopyContains chapters on such topics as Time-integrated fluorescence cumulant analysis, Pulsed Interleaved Excitation, and raster image correlation spectroscopy and number and brightness analysis.Continues the legacy of this premier serial with quality chapters authored by leaders in the fieldCovers fluorescence fluctuation spectroscopyContains chapte

  6. Aorta Fluorescence Imaging by Using Confocal Microscopy

    OpenAIRE

    Wang, Chun-Yang; Tsai, Jui-che; Chuang, Ching-Cheng; Hsieh, Yao-Sheng; Sun, Chia-Wei

    2011-01-01

    The activated leukocyte attacked the vascular endothelium and the associated increase in VEcadherin number was observed in experiments. The confocal microscopic system with a prism-based wavelength filter was used for multiwavelength fluorescence measurement. Multiwavelength fluorescence imaging based on the VEcadherin within the aorta segment of a rat was achieved. The confocal microscopic system capable of fluorescence detection of cardiovascular tissue is a useful tool for measuring the bi...

  7. Integrated Photoacoustic and Fluorescence Confocal Microscopy

    OpenAIRE

    Wang, Yu; Maslov, Konstantin; Kim, Chulhong; Hu, Song; Wang, Lihong V.

    2010-01-01

    We have developed a dual-modality imaging system by integrating optical-resolution photoacoustic microscopy and fluorescence confocal microscopy to provide optical absorption and fluorescence contrasts simultaneously. By sharing the same laser source and objective lens, intrinsically registered photoacoustic and fluorescence images are acquired in a single scan. The micrometer resolution allows imaging of both blood and lymphatic vessels down to the capillary level. Simultaneous photoacoustic...

  8. FAA Fluorescent Penetrant Laboratory Inspections

    Energy Technology Data Exchange (ETDEWEB)

    WINDES,CONNOR L.; MOORE,DAVID G.

    2000-08-02

    The Federal Aviation Administration Airworthiness Assurance NDI Validation Center currently assesses the capability of various non-destructive inspection (NDI) methods used for analyzing aircraft components. The focus of one such exercise is to evaluate the sensitivity of fluorescent liquid penetrant inspection. A baseline procedure using the water-washable fluorescent penetrant method defines a foundation for comparing the brightness of low cycle fatigue cracks in titanium test panels. The analysis of deviations in the baseline procedure will determine an acceptable range of operation for the steps in the inspection process. The data also gives insight into the depth of each crack and which step(s) of the inspection process most affect penetrant sensitivities. A set of six low cycle fatigue cracks produced in 6.35-mm thick Ti-6Al-4V specimens was used to conduct the experiments to produce sensitivity data. The results will document the consistency of the crack readings and compare previous experiments to find the best parameters for water-washable penetrant.

  9. Proteinase-Activated Receptor-1 and Immunomodulatory Effects of a PAR1-Activating Peptide in a Mouse Model of Prostatitis

    Science.gov (United States)

    Stanton, M. Mark; Nelson, Lisa K.; Benediktsson, Hallgrimur; Hollenberg, Morley D.; Buret, Andre G.; Ceri, Howard

    2013-01-01

    Background. Nonbacterial prostatitis has no established etiology. We hypothesized that proteinase-activated receptor-1 (PAR1) can play a role in prostatitis. We therefore investigated the effects of PAR1 stimulation in the context of a new model of murine nonbacterial prostatitis. Methods. Using a hapten (ethanol-dinitrobenzene sulfonic acid- (DNBS-)) induced prostatitis model with both wild-type and PAR1-null mice, we examined (1) the location of PAR1 in the mouse prostate and (2) the impact of a PAR1-activating peptide (TFLLR-NH2: PAR1-TF) on ethanol-DNBS-induced inflammation. Results. Ethanol-DNBS-induced inflammation was maximal at 2 days. In the tissue, PAR1 was expressed predominantly along the apical acini of prostatic epithelium. Although PAR1-TF on its own did not cause inflammation, its coadministration with ethanol-DNBS reduced all indices of acute prostatitis. Further, PAR1-TF administration doubled the prostatic production of interleukin-10 (IL-10) compared with ethanol-DNBS treatment alone. This enhanced IL-10 was not observed in PAR1-null mice and was not caused by the reverse-sequence receptor-inactive peptide, RLLFT-NH2. Surprisingly, PAR1-TF, also diminished ethanol-DNBS-induced inflammation in PAR1-null mice. Conclusions. PAR1 is expressed in the mouse prostate and its activation by PAR1-TF elicits immunomodulatory effects during ethanol-DNBS-induced prostatitis. However, PAR1-TF also diminishes ethanol-DNBS-induced inflammation via a non-PAR1 mechanism by activating an as-yet unknown receptor. PMID:24459330

  10. Profiling gene expression induced by protease-activated receptor 2 (PAR2 activation in human kidney cells.

    Directory of Open Access Journals (Sweden)

    Jacky Y Suen

    Full Text Available Protease-Activated Receptor-2 (PAR2 has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD and key events in tumor progression (angiogenesis, metastasis, but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293, a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2 and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2. Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes, the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2 and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15. Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4 known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents.

  11. Comparaison du Pangola (Digitaria decumbens) et du Stargrass (Cynodon nlemfluensis) exploités par des ovins

    OpenAIRE

    Boval, Maryline

    1989-01-01

    A la Martinique l'utilisation comparée de Digitaria decumbens (Dd) et de Cynodon nlemfuensis (Cn) par des brebis allaitantes a été étudiée pendant une période d'observation de 6 mois. Le cheptel est à un taux élevé de 1 600 kg de poids vif par hectare et par an, obtenu par une fertilisation de 450 kg/ha/an en azote.

  12. Tracking diurnal changes of photosynthesis and evapotranspiration using fluorescence, gas exchange and hyperspectral remote sensing measurements

    Science.gov (United States)

    Wang, S.; Zhang, L.; Guanter, L.; Huang, C.

    2017-12-01

    Photosynthesis and evapotranspiration (ET) are the two most important activities of vegetation and make a great contribution to carbon, water and energy exchanges. Remote sensing provides opportunities for monitoring these processes across time and space. This study focuses on tracking diurnal changes of photosynthesis and evapotranspiration over soybean using multiple measurement techniques. Diurnal changes of both remote sensing-based indicators, including active and passive chlorophyll fluorescence and biophysical-related parameters, including photosynthesis rate (photo) and leaf stomatal conductance (cond), were observed. Results showed that both leaf-level steady-state fluorescence (Fs) and canopy-level solar-induced chlorophyll fluorescence were linearly correlated to photosynthetically active radiation (PAR) during the daytime. A double-peak diurnal change curve was observed for leaf-level photo and cond but not for Fs or SIF. Photo and cond showed a strong nonlinear (second-order) correlation, indicating that photosynthesis, which might be remotely sensed by SIF, has the opportunity to track short-term changes of ET. Results presented in this report will be helpful for better understanding the relationship between remote-sensing-based indices and vegetation's biophysical processes.

  13. Radionuclide X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Cechak, T.

    1994-01-01

    The author's achievements in the title field are summarized and discussed. The following topics are dealt with: (i) principles of radionuclide X-ray fluorescence analysis; (ii) mathematical methods in X-ray fluorescence analysis; (iii) Ross differential filters; (iv) application of radionuclide X-ray fluorescence analysis in the coal industry (with emphasis on the determination of the ash content, sulfur content, and arsenic content of coal); and (v) evaluation of the X-ray fluorescence analyzer from the radiological safety point of view. (P.A.)

  14. Laser induced fluorescence of some plant leaves

    International Nuclear Information System (INIS)

    Helmi, M.S.; Mohamed, M.M.; Amer, R.; Elshazly, O.; Elraey, M.

    1992-01-01

    Laser induced fluorescence (LIF) is successfully used as a technique for remote detection of spectral characteristics of some plants. A pulsed nitrogen laser at 337.1 nm is used to excite cotton, corn and rice leaves. The fluorescence spectrum is detected in the range from 340 nm to 820 nm. It is found that, these plant leaves have common fluorescence maxima at 440 nm, 685 nm and 740 nm. plant leaves are also found to be identifiable by the ratio of the fluorescence intensity at 440 nm to that at 685 nm. The present technique can be further used as a means of assessing, remotely, plant stresses. 5 fig

  15. Measuring fluorescence polarization with a dichrometer.

    Science.gov (United States)

    Sutherland, John C

    2017-09-01

    A method for obtaining fluorescence polarization data from an instrument designed to measure circular and linear dichroism is compared with a previously reported approach. The new method places a polarizer between the sample and a detector mounted perpendicular to the direction of the incident beam and results in determination of the fluorescence polarization ratio, whereas the previous method does not use a polarizer and yields the fluorescence anisotropy. A similar analysis with the detector located axially with the excitation beam demonstrates that there is no frequency modulated signal due to fluorescence polarization in the absence of a polarizer. Copyright © 2017. Published by Elsevier Inc.

  16. Exciton-controlled fluorescence: application to hybridization-sensitive fluorescent DNA probe.

    Science.gov (United States)

    Okamoto, Akimitsu; Ikeda, Shuji; Kubota, Takeshi; Yuki, Mizue; Yanagisawa, Hiroyuki

    2009-01-01

    A hybridization-sensitive fluorescent probe has been designed for nucleic acid detection, using the concept of fluorescence quenching caused by the intramolecular excitonic interaction of fluorescence dyes. We synthesized a doubly thiazole orange-labeled nucleotide showing high fluorescence intensity for a hybrid with the target nucleic acid and effective quenching for the single-stranded state. This exciton-controlled fluorescent probe was applied to living HeLa cells using microinjection to visualize intracellular mRNA localization. Immediately after injection of the probe into the cell, fluorescence was observed from the probe hybridizing with the target RNA. This fluorescence rapidly decreased upon addition of a competitor DNA. Multicoloring of this probe resulted in the simple simultaneous detection of plural target nucleic acid sequences. This probe realized a large, rapid, reversible change in fluorescence intensity in sensitive response to the amount of target nucleic acid, and facilitated spatiotemporal monitoring of the behavior of intracellular RNA.

  17. Time variation of fluorescence lifetime in enhanced cyan fluorescence protein

    International Nuclear Information System (INIS)

    Lee, Soonhyouk; Kim, Soo Yong; Park, Kyoungsook; Jeong, Jinyoung; Chung, Bong Hyun; Kim, Sok Won

    2010-01-01

    The lifetime variations of enhanced cyan fluorescence protein (ECFP) in relatively short integration time bins were studied via time-correlated single photon counting (TCSPC) measurement. We observed that minimum photon counts are necessary for the lifetime estimation to achieve a certain range of variance. The conditions to decrease the variance of lifetime were investigated and the channel width of the measurement of TCSPC data was found to be another important factor for the variance of lifetime. Though the lifetime of ECFP is best fit by a double exponential, a mono exponential fit for the same integration time is more stable. The results may be useful in the analysis of photophysical dynamics for ensemble molecules in short measurement time windows.

  18. Improved Satellite-based Photosysnthetically Active Radiation (PAR) for Air Quality Studies

    Science.gov (United States)

    Pour Biazar, A.; McNider, R. T.; Cohan, D. S.; White, A.; Zhang, R.; Dornblaser, B.; Doty, K.; Wu, Y.; Estes, M. J.

    2015-12-01

    One of the challenges in understanding the air quality over forested regions has been the uncertainties in estimating the biogenic hydrocarbon emissions. Biogenic volatile organic compounds, BVOCs, play a critical role in atmospheric chemistry, particularly in ozone and particulate matter (PM) formation. In southeastern United States, BVOCs (mostly as isoprene) are the dominant summertime source of reactive hydrocarbon. Despite significant efforts in improving BVOC estimates, the errors in emission inventories remain a concern. Since BVOC emissions are particularly sensitive to the available photosynthetically active radiation (PAR), model errors in PAR result in large errors in emission estimates. Thus, utilization of satellite observations to estimate PAR can help in reducing emission uncertainties. Satellite-based PAR estimates rely on the technique used to derive insolation from satellite visible brightness measurements. In this study we evaluate several insolation products against surface pyranometer observations and offer a bias correction to generate a more accurate PAR product. The improved PAR product is then used in biogenic emission estimates. The improved biogenic emission estimates are compared to the emission inventories over Texas and used in air quality simulation over the period of August-September 2013 (NASA's Discover-AQ field campaign). A series of sensitivity simulations will be performed and evaluated against Discover-AQ observations to test the impact of satellite-derived PAR on air quality simulations.

  19. Pars plana Ahmed valve and vitrectomy in patients with glaucoma associated with posterior segment disease.

    Science.gov (United States)

    Wallsh, Josh O; Gallemore, Ron P; Taban, Mehran; Hu, Charles; Sharareh, Behnam

    2013-01-01

    To assess the safety and efficacy of a modified technique for pars plana placement of the Ahmed valve in combination with pars plana vitrectomy in the treatment of glaucoma associated with posterior segment disease. Thirty-nine eyes with glaucoma associated with posterior segment disease underwent pars plana vitrectomy combined with Ahmed valve placement. All valves were placed in the pars plana using a modified technique, without the pars plana clip, and using a scleral patch graft. The 24 eyes diagnosed with neovascular glaucoma had an improvement in intraocular pressure from 37.6 mmHg to 13.8 mmHg and best-corrected visual acuity from 2.13 logarithm of minimum angle of resolution to 1.40 logarithm of minimum angle of resolution. Fifteen eyes diagnosed with steroid-induced glaucoma had an improvement in intraocular pressure from 27.9 mmHg to 14.1 mmHg and best-corrected visual acuity from 1.38 logarithm of minimum angle of resolution to 1.13 logarithm of minimum angle of resolution. Complications included four cases of cystic bleb formation and one case of choroidal detachment and explantation for hypotony. Ahmed valve placement through the pars plana during vitrectomy is an effective option for managing complex cases of glaucoma without the use of the pars plana clip.

  20. Effects of solar PAR and UV radiation on tropical biofouling communities

    KAUST Repository

    Dobretsov, SV

    2010-03-08

    We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum (PAR+UVR), PAR only, and minimal light (reduced PAR and UVR). Terminal restriction fragment length polymorphism analysis demonstrated that different light conditions resulted in the formation of highly different microbial communities. The lowest densities of bacteria were found under the full spectrum treatment, while the lowest densities of diatoms were found in the minimal light treatment. Macrofouling communities consisted of 13 species and differed among light treatments. In the presence of UVR, communities had low species diversity, evenness, and richness, while in minimal light and PAR treatments, communities had high species diversity, evenness, and richness. Similarity percentage (SIMPER) analysis revealed that the tubeworm Hydroides elegans, the alga Ulva (Enteromorpha) sp., and the bivalve Perna viridis were the species responsible for most of the dissimilarities in macrofouling communities among treatments. While densities of H. elegans were similar in the PAR and minimal light treatments, this polychaete had higher growth rates under minimal light conditions. We conclude that UVR and PAR directly control the development of shallow micro- and macrofouling communities by inhibiting the recruitment and growth of sensitive species and promoting the growth of resistant species, but also that these forms of solar radiation influence the surface cues available to competent larvae by altering the development of the microbial community.

  1. The pars intermedia: an anatomic basis for a coordinated vascular response to female genital arousal.

    Science.gov (United States)

    Shih, Cheryl; Cold, Christopher J; Yang, Claire C

    2013-06-01

    The pars intermedia is an area of the vulva that has been inconsistently described in the literature. We conducted anatomic studies to better describe the tissues and vascular structures of the pars intermedia and proposed a functional rationale of the pars intermedia in the female sexual response. Nine cadaveric vulvectomy specimens were used. Each was serially sectioned and stained with hematoxylin and eosin and Masson's trichrome. Histologic ultrastructural description of the pars intermedia. The pars intermedia contains veins traveling longitudinally in the angle of the clitoris, supported by collagen-rich stromal tissues. These veins drain the different vascular compartments of the vulva, including the clitoris, the bulbs, and labia minora; also, the interconnecting veins link the different vascular compartments. The pars intermedia is not composed of erectile tissue, distinguishing it from the erectile tissues of the corpora cavernosa of the clitoris as well as the corpus spongiosum of the clitoral (vestibular) bulbs. The venous communications of the pars intermedia, linking the erectile tissues with the other vascular compartments of the vulva, appear to provide the anatomic basis for a coordinated vascular response during female sexual arousal. © 2012 International Society for Sexual Medicine.

  2. Hunger amidst plenty along the coast of Pará

    Directory of Open Access Journals (Sweden)

    Ivete Nascimento

    2006-08-01

    Full Text Available In this work one analyzes some referring questions to the new significações of the temporality constructed socially enters the artisan fishing of the coast, in the city of Maracanã, using as boundary-maker the concepts the concepts of abundance and famitura the one that they send themselves to the speech in way of life of the past and the gift. It will see as the typical way of life of the rescued past of the memory of old and the meaning of the abundance in the time of the fishing-farmer, the counterpoint with the concept of famitura of the fishing-exclusive of the gift, where the loss surpasses the scope of the strict survival reaching the proper way of life with the weakness of solidarity. This analysis will be given mecanicamente in the conceptual field of the time measured for the tasks and of the time chronometered for the clock. The intensive field work ocurred on Fortaleza of the Mocooca community incorporating data gotten a long the author's experience in the fish artisan thematic of the Pará coast.

  3. Le Web pour enseigner par projets et favoriser la collaboration

    Directory of Open Access Journals (Sweden)

    Sylvie Ratté

    2004-01-01

    Full Text Available L’utilisation du Web présentée dans cet article vient appuyer une démarche pédagogique fondée sur le partage des savoirs. Dans le contexte d’une simulation industrielle, les étudiants d’un cours de programmation avancée doivent apprendre à partager leur expertise, à communiquer clairement leurs questions, à décrire des problèmes et à faire face à des retournements inattendus. Le Web devient un espace de collaboration pour diffuser les requêtes d’un client fictif, les directives, les travaux préliminaires et les ententes. Les résultats obtenus tendent à suggérer que cette approche globale force l’étudiant à mieux planifier, l’invite à mieux formuler et décrire les problèmes, augmente le niveau de collaboration et facilite la production d’analogies. Un système facilitant la logistique entourant la revue par les pairs (récupération des travaux, construction d’une grille d’évaluation et diffusion des résultats est également présenté.

  4. Design of 118 MHz twelfth harmonic cavity of APS PAR

    International Nuclear Information System (INIS)

    Kang, Y.W.; Kustom, R.L.; Bridges, J.F.

    1992-01-01

    Two radio frequency (RF) cavities are needed in the Positron Accumulator Ring (PAR) of the Advanced Photon Source. One is for the first harmonic frequency at 9.8 MHz, and the other is for the twelfth harmonic frequency at 118 MHz. This note reports on the design of the 118 MHz RF cavity. Computer models are used to find the mode frequencies, impedances, Q-factors, and field distributions in the cavity. The computer codes MAFIA, URMEL, and URMEL-T are useful tools which model and simulate the resonance characteristics of a cavity. These codes employ the finite difference method to solve Maxwell's equations. MAFIA is a three-dimensional problem solver and uses square patches to approximate the inner surface of a cavity. URMEL and URMEL-T are two-dimensional problem solvers and use rectangular and triangular meshes, respectively. URMEL-T and MAFIA can handle problems with arbitrary dielectric materials located inside the boundary. The cavity employs a circularly cylindrical ceramic window to limit the vacuum to the beam pipe. The ceramic window used in the modeling will have a wall thickness of 0.9 cm. This wall thickness is not negligible in determining the resonant frequencies of the cavity. In the following, results of two- and three-dimensional modeling of the cavities using the URMEL-T and MAFIA codes are reported

  5. Characterization of ParTI Phoswiches Using Charged Pion Beams

    Science.gov (United States)

    Churchman, Emily; Zarrella, Andrew; Youngs, Michael; Yennello, Sherry

    2017-09-01

    The Partial Truncated Icosahedron (ParTI) detector array consists of 15 phoswiches. Each phoswich is made of two scintillating components - a thallium-doped cesium iodide (CsI(Tl)) crystal and an EJ-212 scintillating plastic - coupled to a photomultiplier tube. Both materials have different scintillation times and are sensitive to both charged and neutral particles. The type of particle and amount of energy deposited determine the shape of the scintillation pulse as a function of time. By integrating the fast and slow signals of the scintillation pulses, a ``Fast vs. Slow Integration'' plot can be created that produces particle identification lines based on the energy deposited in the scintillating materials. Four of these phoswiches were taken to the Paul Scherrer Institute (PSI) in Switzerland where π + , π-, and proton beams were scattered onto the phoswiches to demonstrate their particle identification (PID) capabilities. Using digitizers to record the detector response waveforms, pions can also be identified by the characteristic decay pulse of the muon daughters.

  6. Monitoreo de parásitos en efluentes domiciliarios

    Directory of Open Access Journals (Sweden)

    Semenas Liliana

    1999-01-01

    Full Text Available OBJETIVO: Evaluar la presencia de parásitos en efluentes semisólidos y líquidos en distintas localidades de la Patagonia argentina considerando que ésta es una de las restricciones para su uso. MÉTODOS: Las muestras tomadas en 4 Plantas de Tratamiento de Efluentes Domiciliarios se analizaron siguiendo las normativas de Environmental Protection Agency, Organización Mundial de la Salud, Standard Methods for Examination of Water and Wastewater y de algunas clasificaciones. RESULTADOS: Solamente 2 de las 6 muestras de semisólidos analizadas tenían huevos de Ascaris lumbricoides no viables. De las 10 muestras líquidas, solamente 2 no tenían huevos mientras las restantes tenían patógenos de las categorías I (Giardia sp., Hymenolepis diminuta y Enterobius vermicularis y III (Ascaris lumbricoides, Ancylostoma duodenale y Trichuris trichiura. CONCLUSIONES: Todas las muestras de semisólidos analizadas fueron aptas para su uso como fertilizantes porque no se registró en ninguna de ellas la presencia de huevos viables de Ascaris lumbricoides y solamente 6 de las muestras líquidas fueron aptas para riego por carecer de huevos o por ser su concentración igual o inferior a 1 huevo por litro.

  7. MMP-1/PAR-1 signal transduction axis and its prognostic impact in esophageal squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Hong-hua Peng

    2012-01-01

    Full Text Available The matrix metalloprotease-1 (MMP-1/protease-activated receptor-1 (PAR-1 signal transduction axis plays an important role in tumorigenesis. To explore the expression and prognostic value of MMP-1 and PAR-1 in esophageal squamous cell carcinoma (ESCC, we evaluated the expression of two proteins in resected specimens from 85 patients with ESCC by immunohistochemistry. Sixty-two (72.9% and 58 (68.2% tumors were MMP-1- and PAR-1-positive, respectively, while no significant staining was observed in normal esophageal squamous epithelium. MMP-1 and PAR-1 overexpression was significantly associated with tumor node metastasis (TNM stage and regional lymph node involvement. Patients with MMP-1- and PAR-1-positive tumors, respectively, had poorer disease-free survival (DFS than those with negative ESCC (P = 0.002 and 0.003, respectively. Univariate analysis showed a significant relationship between TNM stage [hazard ratio (HR = 2.836, 95% confidence interval (CI = 1.866-4.308], regional lymph node involvement (HR = 2.955, 95%CI = 1.713-5.068, MMP-1 expression (HR = 2.669, 95%CI = 1.229-6.127, and PAR-1 expression (HR = 1.762, 95%CI = 1.156-2.883 and DFS. Multivariate analysis including the above four parameters identified TNM stage (HR = 2.035, 95%CI = 1.167-3.681, MMP-1 expression (HR = 2.109, 95%CI = 1.293-3.279, and PAR-1 expression (HR = 1.967, 95%CI = 1.256-2.881 as independent and significant prognostic factors for DFS. Our data suggest for the first time that MMP-1 and PAR-1 were both overexpressed in ESCC and are novel predictors of poor patient prognosis after curative resection. The MMP-1/PAR-1 signal transduction axis might be a new therapeutic target for future therapies tailored against ESCC.

  8. MMP-1/PAR-1 signal transduction axis and its prognostic impact in esophageal squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hong-hua; Zhang, Xi; Cao, Pei-guo [Department of Oncology, the Third Xiangya Hospital, Central South University, Changsha, Hunan Province (China)

    2011-11-18

    The matrix metalloprotease-1 (MMP-1)/protease-activated receptor-1 (PAR-1) signal transduction axis plays an important role in tumorigenesis. To explore the expression and prognostic value of MMP-1 and PAR-1 in esophageal squamous cell carcinoma (ESCC), we evaluated the expression of two proteins in resected specimens from 85 patients with ESCC by immunohistochemistry. Sixty-two (72.9%) and 58 (68.2%) tumors were MMP-1- and PAR-1-positive, respectively, while no significant staining was observed in normal esophageal squamous epithelium. MMP-1 and PAR-1 overexpression was significantly associated with tumor node metastasis (TNM) stage and regional lymph node involvement. Patients with MMP-1- and PAR-1-positive tumors, respectively, had poorer disease-free survival (DFS) than those with negative ESCC (P = 0.002 and 0.003, respectively). Univariate analysis showed a significant relationship between TNM stage [hazard ratio (HR) = 2.836, 95% confidence interval (CI) = 1.866-4.308], regional lymph node involvement (HR = 2.955, 95%CI = 1.713-5.068), MMP-1 expression (HR = 2.669, 95%CI = 1.229-6.127), and PAR-1 expression (HR = 1.762, 95%CI = 1.156-2.883) and DFS. Multivariate analysis including the above four parameters identified TNM stage (HR = 2.035, 95%CI = 1.167-3.681), MMP-1 expression (HR = 2.109, 95%CI = 1.293-3.279), and PAR-1 expression (HR = 1.967, 95%CI = 1.256-2.881) as independent and significant prognostic factors for DFS. Our data suggest for the first time that MMP-1 and PAR-1 were both overexpressed in ESCC and are novel predictors of poor patient prognosis after curative resection. The MMP-1/PAR-1 signal transduction axis might be a new therapeutic target for future therapies tailored against ESCC.

  9. Conservation problems with paintings containing fluorescent layers of paint

    Directory of Open Access Journals (Sweden)

    Stefanie De Winter

    2010-11-01

    Full Text Available L’artiste moderne cherche continuellement de nouvelles techniques. Des nouveaux matériaux tels que l’éponge, le polyester, le sable, etc. sont devenus courants. Ces développements amènent de nouveaux problèmes dans le domaine de la conservation (préventive des matériaux en question. Chaque matériau doit être analysé individuellement afin de préserver  le mieux possible l’intention de l’artiste à long terme. La présente recherche concerne des matériaux très récents: les pigments et les couleurs fluorescentes. Ces derniers n’ont fait leur apparition qu’au vingtième siècle. Pour cette raison les données concernant leur dégradation et leur conservation sont peu nombreuses. La majorité des tableaux fluorescents sont conçus pour être montrés sous éclairage UV. En cas de dommage, si l’œuvre a besoin d’être retouchée, ceci pose un grand problème esthétique. La retouche devient visible sous les lampes UV. La première partie de la recherche concerne la composition des différentes sortes de pigments et de peintures. Par la suite, les différentes causes de dégradation- lumière UV, chaleur, etc.- sont analysées en détail. Pour conclure, un possible remède est proposé.In modern art we can see that artists are breaking with traditional techniques. New materials like sponge, polyester, sand, etc. are being used. This causes a lot of new problems in the (preventive conservation of works containing these materials. Every material needs to be researched individually so the exact intention of the artist can be preserved for a (relatively long period. My research is about very recent materials: fluorescent pigments and paints. These only started to be used by artists from the 60’s. That's why there is not much information about their aging and ways to (preventively conserve them. A lot of fluorescent paintings are meant to be shown under UV-light. If a fluorescent painting has damage and needs to be retouched

  10. Molecules for Fluorescence Detection of Specific Chemicals

    Science.gov (United States)

    Fedor, Steve

    2008-01-01

    A family of fluorescent dye molecules has been developed for use in on-off fluorescence detection of specific chemicals. By themselves, these molecules do not fluoresce. However, when exposed to certain chemical analytes in liquid or vapor forms, they do fluoresce (see figure). These compounds are amenable to fixation on or in a variety of substrates for use in fluorescence-based detection devices: they can be chemically modified to anchor them to porous or non-porous solid supports or can be incorporated into polymer films. Potential applications for these compounds include detection of chemical warfare agents, sensing of acidity or alkalinity, and fluorescent tagging of proteins in pharmaceutical research and development. These molecules could also be exploited for use as two-photon materials for photodynamic therapy in the treatment of certain cancers and other diseases. A molecule in this family consists of a fluorescent core (such as an anthracene or pyrene) attached to two end groups that, when the dye is excited by absorption of light, transfer an electron to the core, thereby quenching the fluorescence. The end groups can be engineered so that they react chemically with certain analytes. Upon reaction, electrons on the end groups are no longer available for transfer to the core and, consequently, the fluorescence from the core is no longer quenched. The chemoselectivity of these molecules can be changed by changing the end groups. For example, aniline end groups afford a capability for sensing acids or acid halides (including those contained in chemical warfare agents). Pyridine or bipyridyl end groups would enable sensing of metal ions. Other chemicals that can be selectively detected through suitable choice of end groups include glucose and proteins. Moreover, the fluorescent cores can be changed to alter light-absorption and -emission characteristics: anthracene cores fluoresce at wavelengths around 500 nm, whereas perylene cores absorb and emit at

  11. Fluorescence spectroscopy for medical and environmental diagnostics

    International Nuclear Information System (INIS)

    Johansson, Jonas.

    1993-09-01

    Fluorescence spectroscopy can be used for diagnostics in medical and environmental applications. The many aspects of fluorescence emission are utilized to enhance the accuracy of the diagnosis. A fluorescence detection system, based on nitrogen laser or dye laser excitation and optical multichannel detection, was constructed, and fluorescence spectra from human malignant tumours of various origins, were recorded. Tumour demarcation was observed using exogenous chromophores, as well as the endogenous tissue fluorescence. In particular, δ-amino levulinic acid was found to provide very good tumour demarcation. A multi-colour imaging system capable of simultaneous recording of four fluorescence images at selected wavelengths, was developed. Examples of processed images, based on the four sub-images, are shown for malignant tumours. In addition, data from photodynamic treatment of human malignant tumours are presented. Autofluorescence spectra from excised pieces of human atherosclerotic aorta and atherosclerotic coronary segment were found to be different from those of non-diseased vessels. Furthermore, fluorescence decay curves from atherosclerotic samples were found to differ from those of non-diseased samples. It is concluded that both spectral and temporal information should be utilized to enhance the demarcation. Methods for obtaining fluorescence data free from interference from blood, with applications to in vivo laser angioplasty of atherosclerosis, are discussed. The optical multichannel system and the multi-colour imaging system were integrated with a remote sensing system, originally used for environmental measurements, to obtain fluorescence spectra as well as fluorescence images of plants at a distance of up to 100 m. The fluorescence data from plants subject to environmental stress or senescent plants were found to differ from those obtained from healthy vegetation. 359 refs

  12. Prognostic value of suPAR and hs-CRP on cardiovascular disease

    DEFF Research Database (Denmark)

    Diederichsen, Marie Zöga; Diederichsen, Søren Zöga; Mickley, Hans

    2018-01-01

    Background and aims: Studies have shown that soluble urokinase Plasminogen Activator Receptor (suPAR) and CRP (both inflammatory markers) and coronary artery calcification (CAC) are independent risk predictors for cardiovascular (CV) disease. The aim of this study is to assess whether suPAR and CRP...... have an increased predictive prognostic value beyond the traditional CV risk factors and the CAC score. Methods: A population sample of 1179 subjects, free of CV disease was included. The subjects underwent traditional CV risk evaluation, CAC assessment and blood sampling for suPAR and CRP. CV events...

  13. Profils des enfants infectes par le vih en debut du traitement ...

    African Journals Online (AJOL)

    But : Décrire les profils des enfants infectés par le VIH au début du traitement antirétroviral. Matériels et méthode: Les dossiers des enfants infectés par le VIH dans la région maritime ont été analysés de mai 2008 à février 2010 par le comité thérapeutique. Résultats: Parmi les 96 dossiers analysés, 66,67% venaient du ...

  14. Les dispensées par fantaisie en éducation physique et sportive ...

    African Journals Online (AJOL)

    Cette étude vise à comprendre les raisons avancées par les élèves dispensés par fantaisie des cours d'EPS, pour justifier leur attitude et principalement leur forfait. Une enquête par questionnaire écrit a été menée dans 13 établissements publics de la ville de Porto-Novo au Bénin. Au total, 203 élèves parmi les 771 élèves ...

  15. MODELISATION DE LA CINETIQUE CHIMIQUE DANS LA REDUCTION DES OXYDES D4AZOTE PAR DECHARGE COURONNE.

    OpenAIRE

    MEDJAHDI, Sarah ines

    2015-01-01

    CE TRAVAIL DE recherche rentre dans le cadre général de modélisation de la réduction des oxydes d'azote . l'utilisation des réacteurs a plasma froid non-thermique généré par des décharges couronnes est actuellement l'une des techniques les puis promettre .ses pour la destruction des oxydes d'azote .en effet , le traitement des gaz pollués par les décharges couronnes est notamment rendu possible par la multiplication des décharges Électriques .

  16. Thrombin induces rapid PAR1-mediated non-classical FGF1 release

    International Nuclear Information System (INIS)

    Duarte, Maria; Kolev, Vihren; Soldi, Raffaella; Kirov, Alexander; Graziani, Irene; Oliveira, Silvia Marta; Kacer, Doreen; Friesel, Robert; Maciag, Thomas; Prudovsky, Igor

    2006-01-01

    Thrombin induces cell proliferation and migration during vascular injury. We report that thrombin rapidly stimulated expression and release of the pro-angiogenic polypeptide fibroblast growth factor 1 (FGF1). Thrombin failed to induce FGF1 release from protease-activated receptor 1 (PAR1) null fibroblasts, indicating that this effect was dependent on PAR1. Similarly to thrombin, FGF1 expression and release were induced by TRAP, a specific oligopeptide agonist of PAR1. These results identify a novel aspect of the crosstalk between FGF and thrombin signaling pathways which both play important roles in tissue repair and angiogenesis

  17. Complexation de l'aluminium par des hétéropolyanions lacunaires ...

    African Journals Online (AJOL)

    L'objectif visé par cette étude est la dépollution des eaux à partir de la complexation d'un métal toxique, l'aluminium en solution, par des hétéropolyanions lacunaires (HPA) de type Dawson. Les complexes formés sont récupérés par membrane liquide émulsionnée (MEL).Les résultats de la complex1ation de l'aluminium ...

  18. Influence of P-Reactor operation on the aquatic ecology of Par Pond: a literature review

    International Nuclear Information System (INIS)

    Wilde, E.W.; Tilly, L.J.

    1985-02-01

    Par Pond is a 1012 hectare reservoir that was constructed in 1958 to provide cooling water for Savannah River nuclear reactors. The purpose of this report is to summarize all known studies on the Par Pond system and point out demonstrable or probable effects that can be correlated with reactor operations. Reactor operation effects the Par Pond ecosystem through: (1) pumping, (2) thermal alteration, and (3) the addition of Savannah River makeup water. The influence of each of these factors is discussed. 108 references, 24 figures, 34 tables. (MF)

  19. Monoradiculopathy and secondary segmental instability caused by postoperative pars interarticularis fracture: a case report.

    Science.gov (United States)

    Kaner, Tuncay; Tutkan, Ibrahim

    2009-04-01

    Instability can develop after lumbar spinal surgery. What is also known as secondary segmental instability is one of the important causes of failed back syndrome. In this paper, we described a 45-year-old female patient who was diagnosed with secondary segmental instability caused by left L3 pars interarticularis fracture after a high lumbar disc surgery and was subsequently treated with re-operation. We evaluated the clinical course, diagnosis, and treatment methods for secondary segmental instability caused by postoperative pars interarticularis fracture. Furthermore, we emphasized the importance of preserving the pars interarticularis during upper lumbar disc surgeries in order to avoid a potential stress fracture.

  20. ULTRAFINE FLUORESCENT DIAMONDS IN NANOTECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Kanyuk M. I.

    2014-07-01

    Full Text Available The purpose of the work is to summarize the literature data concerning ultrafine diamonds, namely their industrial production, as well as considerable photostability and biocompatibility that promote their use in modern visualization techniques. It is shown that due to the unique physical properties, they are promising materials for using in nanotechnology in the near future. Possibility of diverse surface modification, small size and large absorption surface are the basis for their use in different approaches for drug and gene delivery into a cell. The changes in the properties of nanodiamond surface modification methods of their creation, stabilization and applications are described. It can be said that fluorescent surface-modified nanodiamonds are a promising target in various research methods that would be widely used for labeling of living cells, as well as in the processes of genes and drugs delivery into a cell.

  1. Influencia de los parámetros de proceso, en el comportamiento del parámetro vibración absoluta en turbinas de vapor.

    Directory of Open Access Journals (Sweden)

    F. de la Torre Silva

    2008-01-01

    Full Text Available Este trabajo muestra el estudio realizado en turbinas de vapor de pequeña capacidad de generación de las centrales termoeléctricas cubanas, relacionadas con la influencia estadística entre parámetros de proceso de la turbina, respecto al parámetro vibración absoluta, medidos en las chumaceras de la turbina. Se utilizan las bases de datos de los sistemas de monitoreado on-line de la turbina. Se exponen las relaciones existentes entre los principales parámetros seleccionados para este estudio.This work show the study in small steam turbine capacity of generation in cubans thermoelectric power station to relative with statistical influence between steam process parameters regarding absolute vibration parameter, in the steam housing measurements. Themselves use database as steam on-line monitoring systems. Expose the existing relation between the principal selection parameters for this study.

  2. Bridging fluorescence microscopy and electron microscopy

    NARCIS (Netherlands)

    Giepmans, Ben N. G.

    Development of new fluorescent probes and fluorescence microscopes has led to new ways to study cell biology. With the emergence of specialized microscopy units at most universities and research centers, the use of these techniques is well within reach for a broad research community. A major

  3. Enhanced localized fluorescence in plasmonic nanoantennae

    DEFF Research Database (Denmark)

    Bakker, R.M.; Yuan, H.-K.; Liu, Z.

    2008-01-01

    in fluorescence that reaches 100 times enhancement. Near-field excitation shows enhanced fluorescence from a single nanoantenna localized in a subwavelength area of similar to 0.15 mu m(2). The polarization of enhanced emission is along the main antenna axis. These observed experimental results are important...

  4. Control of excitation in the fluorescence microscope.

    Science.gov (United States)

    Lea, D J; Ward, D J

    1979-01-01

    In fluorescence microscopy image brightness and contrast and the rate of fading depend upon the intensity of illumination of the specimen. An iris diaphragm or neutral density filters may be used to reduce fluorescence excitation. Also the excitation bandwidth may be varied by using a broad band exciter filter with a set of interchangeable yellow glass filters at the lamphouse.

  5. Fluorescent nanoparticles for intracellular sensing: a review.

    Science.gov (United States)

    Ruedas-Rama, Maria J; Walters, Jamie D; Orte, Angel; Hall, Elizabeth A H

    2012-11-02

    Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Xanthines Studied via Femtosecond Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    Pascale Changenet-Barret

    2016-12-01

    Full Text Available Xanthines represent a wide class of compounds closely related to the DNA bases adenine and guanine. Ubiquitous in the human body, they are capable of replacing natural bases in double helices and give rise to four-stranded structures. Although the use of their fluorescence for analytical purposes was proposed, their fluorescence properties have not been properly characterized so far. The present paper reports the first fluorescence study of xanthine solutions relying on femtosecond spectroscopy. Initially, we focus on 3-methylxanthine, showing that this compound exhibits non-exponential fluorescence decays with no significant dependence on the emission wavelength. The fluorescence quantum yield (3 × 10−4 and average decay time (0.9 ps are slightly larger than those found for the DNA bases. Subsequently, we compare the dynamical fluorescence properties of seven mono-, di- and tri-methylated derivatives. Both the fluorescence decays and fluorescence anisotropies vary only weakly with the site and the degree of methylation. These findings are in line with theoretical predictions suggesting the involvement of several conical intersections in the relaxation of the lowest singlet excited state.

  7. Absorbance and fluorescence studies on porphyrin Nanostructures ...

    African Journals Online (AJOL)

    The aim of this work was to study some photophysical properties of PNR for application as light harvester in dye sensitized solar cells. These properties included absorbance, fluorescence, and fluorescence quantum yield and lifetime. The results of Transmission Electron Microscope (TEM) images showed the formation of ...

  8. Examining Thermally Sprayed Coats By Fluorescence Microscopy

    Science.gov (United States)

    Street, Kenneth W., Jr.; Leonhardt, Todd A.

    1994-01-01

    True flaws distinquished from those induced by preparation of specimens. Fluorescence microscopy reveals debonding, porosity, cracks, and other flaws in specimens of thermally sprayed coating materials. Specimen illuminated, and dye it contains fluoresces, emitting light at different wavelength. Filters emphasize contrast between excitation light and emission light. Specimen viewed directly or photographed on color film.

  9. Peptide-stabilized, fluorescent silver nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon; Vosch, Tom André Jos; Jensen, Knud Jørgen

    2016-01-01

    Few-atom silver nanoclusters (AgNCs) can exhibit strong fluorescence; however, they require ligands to prevent aggregation into larger nanoparticles. Fluorescent AgNCs in biopolymer scaffolds have so far mainly been synthesized in solution, and peptides have only found limited use compared to DNA...

  10. Red and green fluorescence from oral biofilms

    NARCIS (Netherlands)

    Volgenant, C.M.C.; Hoogenkamp, M.A.; Krom, B.P.; Janus, M.M.; ten Cate, J.M.; de Soet, J.J.; Crielaard, W.; van der Veen, M.H.

    2016-01-01

    Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis.

  11. Fluorescence lifetime imaging using light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Gordon T; Munro, Ian; Poher, Vincent; French, Paul M W; Neil, Mark A A [Blackett Laboratory, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Elson, Daniel S [Institute of Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Hares, Jonathan D [Kentech Instruments Ltd, Unit 9, Hall Farm Workshops, South Moreton, Didcot, Oxfordshire, OX11 9AG (United Kingdom)], E-mail: gordon.kennedy@imperial.ac.uk

    2008-05-07

    We demonstrate flexible use of low cost, high-power light emitting diodes as illumination sources for fluorescence lifetime imaging (FLIM). Both time-domain and frequency-domain techniques have been implemented at wavelengths spanning the range 450-640 nm. Additionally, we demonstrate optically sectioned fluorescence lifetime imaging by combining structured illumination with frequency-domain FLIM.

  12. A sensitive fluorescent sensor of lanthanide ions

    CERN Document Server

    Bekiari, V; Lianos, P

    2003-01-01

    A fluorescent probe bearing a diazostilbene chromophore and a benzo-15-crown-5 ether moiety is a very efficient sensor of lanthanide ions. The ligand emits strong fluorescence only in the presence of specific ions, namely lanthanide ions, while the emission wavelength is associated with a particular ion providing high sensitivity and resolution.

  13. Efficacy and safety of the pars plana clip in the Ahmed valve device inserted via the pars plana in patients with refractory glaucoma

    Directory of Open Access Journals (Sweden)

    Manuel Diaz-Llopis

    2010-05-01

    Full Text Available Manuel Diaz-Llopis1,2,3, David Salom1,3, Salvador García-Delpech1,2,3, Patricia Udaondo1,3, Jose Maria Millan3,5, J Fernando Arevalo61Department of Ophthalmology, La Fe University Hospital of Valencia, Valencia, Spain; 2Department of Ophthalmology of the Valencia University, Valencia, Spain; 3Biomedical Network Research Centre on Rare Diseases (CIBERER, Valencia, Spain; 4Catholic University San Vicente Martir, Valencia, Spain; 5Department of Genetics, La Fe University Hospital of Valencia, Valencia, Spain; 6Clinica Oftalmologica Centro Caracas, Retina and VItreous Service, Caracas, DC, VenezuelaPurpose: To evaluate the efficacy and safety of the pars plana clip (PPC in the Ahmed valve tube inserted via the pars plana in patients with secondary refractory glaucomas.Methods: Prospective and interventional case series that included 10 patients with secondary refractory glaucoma. The pars plana vitrectomy and the implant of the modified tube were performed during the same surgery. Control of intraocular pressure (IOP and the development of intra- and postoperative complications were evaluated during the follow-up.Results: Follow-up time was twelve months in all the patients. Control of IOP was achieved in 90% of patients, and 70% needed no antiglaucoma treatment. The complications that occurred were transient hypotony in three cases, choroidal detachment in two cases, and one case of intraocular hemorrhage. No case of tube extrusion or tube kink was observed.Conclusions: Our data suggests that implantation of the Ahmed tube modified with the PPC via the pars plana is safe and effective in patients with secondary refractory glaucomas. Keywords: pars plana clip, Ahmed valve, refractory glaucoma, pars plana vitrectomy

  14. 194 Évaluation de l'efficacité de l'insecticide Tricel 480 EC ...

    African Journals Online (AJOL)

    PR BOKO

    phytosanitaires par les agriculteurs, induit l'apparition de populations résistantes de ravageurs tel que. Plutellaxylostella [4], des risques sanitaires importants tels que les résidus de pesticides et de nitrates dans les produits alimentaires et les sols [5]. Parmi ces cultures maraichères, le chou fait partie des plus attaquées par ...

  15. Intense fluorescence of Au 20

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chongqi; Harbich, Wolfgang; Sementa, Luca; Ghiringhelli, Luca; Apra, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Brune, Harald

    2017-08-21

    Ligand-protected Au clusters are non-bleaching fluorescence markers in bio- and medical applications. We show that their fluorescence is an intrinsic property of the Au cluster itself. We find a very intense and sharp fluorescence peak located at λ =739.2 nm (1.68 eV) for Au20 clusters in a Ne matrix held at 6 K. The fluorescence reflects the HOMO-LUMO diabatic bandgap of the cluster. The cluster shows a very rich absorption fine structure reminiscent of well defined molecule-like quantum levels. These levels are resolved since Au20 has only one stable isomer (tetrahedral), therefore our sample is mono-disperse in cluster size and conformation. Density-functional theory (DFT) and time-dependent DFT calculations clarify the nature of optical absorptionand predict both main absorption peaks and intrinsic fluorescence in good agreement with experiment.

  16. Boronic acids for fluorescence imaging of carbohydrates.

    Science.gov (United States)

    Sun, Xiaolong; Zhai, Wenlei; Fossey, John S; James, Tony D

    2016-02-28

    "Fluorescence imaging" is a particularly exciting and rapidly developing area of research; the annual number of publications in the area has increased ten-fold over the last decade. The rapid increase of interest in fluorescence imaging will necessitate the development of an increasing number of molecular receptors and binding agents in order to meet the demand in this rapidly expanding area. Carbohydrate biomarkers are particularly important targets for fluorescence imaging given their pivotal role in numerous important biological events, including the development and progression of many diseases. Therefore, the development of new fluorescent receptors and binding agents for carbohydrates is and will be increasing in demand. This review highlights the development of fluorescence imaging agents based on boronic acids a particularly promising class of receptors given their strong and selective binding with carbohydrates in aqueous media.

  17. Multispectral system for medical fluorescence imaging

    International Nuclear Information System (INIS)

    Andersson, P.S.; Montan, S.; Svanberg, S.

    1987-01-01

    The principles of a powerful multicolor imaging system for tissue fluorescence diagnostics are discussed. Four individually spectrally filtered images are formed on a matrix detector by means of a split-mirror arrangement. The four images are processed in a computer, pixel by pixel, by means of mathematical operations, leading to an optimized contrast image, which enhances a selected feature. The system is being developed primarily for medical fluorescence imaging, but has wide applications in fluorescence, reflectance, and transmission monitoring related to a wide range of industrial and environmental problems. The system operation is described for the case of linear imaging on a diode array detector. Laser-induced fluorescence is used for cancer tumor and arteriosclerotic plaque demarcation using the contrast enhancement capabilities of this imaging system. Further examples of applications include fluorescing minerals and flames

  18. Holograms preparation using commercial fluorescent benzyl

    Energy Technology Data Exchange (ETDEWEB)

    Dorantes-GarcIa, V; Olivares-Perez, A; Ordonez-Padilla, M J; Mejias-Brizuela, N Y, E-mail: valdoga@Hotmail.com, E-mail: olivares@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Coordinacion de Optica, Calle Luis Enrique Erro N0 1, Santa Maria Tonantzintla, Puebla (Mexico)

    2011-01-01

    We have been able to make holograms with substances such as fluorescence thought of light blue laser to make transmissions holograms, using ammonium dichromate as photo-sensitizer and polyvinyl alcohol (PVA) as matrix. Ammonium dichromate inhibit the fluorescence properties of inks, both mixed in a (PVA) matrix, but we avoid this chemical reaction and we show the results to use the method of painting hologram with fluorescents ink and we describe how the diffraction efficiency parameter changes as a function of the ink absorbed by the emulsion recorded with the gratings, we got good results, making holographic gratings with a blue light from laser diode 470 nm. And we later were painting with fluorescent ink, integrating fluorescence characteristics to the hologram.

  19. Fiber optical assembly for fluorescence spectrometry

    Science.gov (United States)

    Carpenter, II, Robert W.; Rubenstein, Richard; Piltch, Martin; Gray, Perry

    2010-12-07

    A system for analyzing a sample for the presence of an analyte in a sample. The system includes a sample holder for containing the sample; an excitation source, such as a laser, and at least one linear array radially disposed about the sample holder. Radiation from the excitation source is directed to the sample, and the radiation induces fluorescent light in the sample. Each linear array includes a plurality of fused silica optical fibers that receive the fluorescent light and transmits a fluorescent light signal from the first end to an optical end port of the linear array. An end port assembly having a photo-detector is optically coupled to the optical end port. The photo-detector detects the fluorescent light signal and converts the fluorescent light signal into an electrical signal.

  20. Outcome of early pars plana vitrectomy in exogenous endophthalmitis

    International Nuclear Information System (INIS)

    Dar, A.J.; Islam, Q.U.; Hanif, M.K.

    2013-01-01

    Objective: To evaluate the role of early pars plana vitrectomy (PPV) in cases of exogenous endophthalmitis in terms of final visual outcome and to determine association between various study variables and final visual outcome. Study Design: Quasi experimental study. Place and Duration of Study: Armed Forces Institute of Ophthalmology (AFIO) Rawalpindi, from Aug 2010 to May 2012. Patients and Methods: Eleven cases of exogenous endophthalmitis (post surgical/post traumatic) were managed surgically through 20 G or 23/25 G complete and early PPV. Vitreous aspirate/explanted intraocular lens (IOL) were sent for culture and sensitivity in all cases. Intra and post operative complications were recorded and best corrected visual acuity (BCVA) at 3 months post operative interval was taken as final visual acuity. Results: Median age of study population was 55 years with male preponderance (64%). Approximately 2/3 rd of study population developed endophthalmitis within 6 weeks of surgery/trauma and 55% of patients were operated within 2 weeks of presentation. Positive culture from vitreous aspirate/IOL explant was obtained in 27% of cases. All the patients had initial BCVA in the range of counting finger (CF) at 2 meter to perception of light (PL+). However, 18% of the patients achieved final BCVA of 6/12 or better and 64% achieved final BCVA of 6/36 or better. Maculopathy (macular scar, macular pucker), corneal decompensation, corneal opacity and raised intraocular pressure were the major complications associated with compromised visual outcome. Conclusion: With the advancement in vitreoretinal surgical techniques and availability of more sophisticated viewing and illumination systems, early and complete vitrectomy for post operative or post traumatic endophthalmitis results in favorable visual outcome and early rehabilitation. (author)

  1. Intrinsic and integrative properties of substantia nigra pars reticulata neurons

    Science.gov (United States)

    Zhou, Fu-Ming; Lee, Christian R.

    2011-01-01

    The GABA projection neurons of the substantia nigra pars reticulata (SNr) are output neurons for the basal ganglia and thus critical for movement control. Their most striking neurophysiological feature is sustained, spontaneous high frequency spike firing. A fundamental question is: what are the key ion channels supporting the remarkable firing capability in these neurons? Recent studies indicate that these neurons express tonically active TRPC3 channels that conduct a Na-dependent inward current even at hyperpolarized membrane potentials. When the membrane potential reaches −60 mV, a voltage-gated persistent sodium current (INaP) starts to activate, further depolarizing the membrane potential. At or slightly below −50 mV, the large transient voltage-activated sodium current (INaT) starts to activate and eventually triggers the rapid rising phase of action potentials. SNr GABA neurons have a higher density of (INaT), contributing to the faster rise and larger amplitude of action potentials, compared with the slow-spiking dopamine neurons. INaT also recovers from inactivation more quickly in SNr GABA neurons than in nigral dopamine neurons. In SNr GABA neurons, the rising phase of the action potential triggers the activation of high-threshold, inactivation-resistant Kv3-like channels that can rapidly repolarize the membrane. These intrinsic ion channels provide SNr GABA neurons with the ability to fire spontaneous and sustained high frequency spikes. Additionally, robust GABA inputs from direct pathway medium spiny neurons in the striatum and GABA neurons in the globus pallidus may inhibit and silence SNr GABA neurons, whereas glutamate synaptic input from the subthalamic nucleus may induce burst firing in SNr GABA neurons. Thus, afferent GABA and glutamate synaptic inputs sculpt the tonic high frequency firing of SNr GABA neurons and the consequent inhibition of their targets into an integrated motor control signal that is further fine-tuned by neuromodulators

  2. Fluorescent Probes and Fluorescence (Microscopy Techniques — Illuminating Biological and Biomedical Research

    Directory of Open Access Journals (Sweden)

    Gregor P. C. Drummen

    2012-11-01

    Full Text Available Fluorescence, the absorption and re-emission of photons with longer wavelengths, is one of those amazing phenomena of Nature. Its discovery and utilization had, and still has, a major impact on biological and biomedical research, since it enables researchers not just to visualize normal physiological processes with high temporal and spatial resolution, to detect multiple signals concomitantly, to track single molecules in vivo, to replace radioactive assays when possible, but also to shed light on many pathobiological processes underpinning disease states, which would otherwise not be possible. Compounds that exhibit fluorescence are commonly called fluorochromes or fluorophores and one of these fluorescent molecules in particular has significantly enabled life science research to gain new insights in virtually all its sub-disciplines: Green Fluorescent Protein. Because fluorescent proteins are synthesized in vivo, integration of fluorescent detection methods into the biological system via genetic techniques now became feasible. Currently fluorescent proteins are available that virtually span the whole electromagnetic spectrum. Concomitantly, fluorescence imaging techniques were developed, and often progress in one field fueled innovation in the other. Impressively, the properties of fluorescence were utilized to develop new assays and imaging modalities, ranging from energy transfer to image molecular interactions to imaging beyond the diffraction limit with super-resolution microscopy. Here, an overview is provided of recent developments in both fluorescence imaging and fluorochrome engineering, which together constitute the “fluorescence toolbox” in life science research.

  3. PAR-1 and thrombin: the ties that bind the microenvironment to melanoma metastasis.

    Science.gov (United States)

    Zigler, Maya; Kamiya, Takafumi; Brantley, Emily C; Villares, Gabriel J; Bar-Eli, Menashe

    2011-11-01

    Progression of melanoma is dependent on cross-talk between tumor cells and the adjacent microenvironment. The thrombin receptor, protease-activated receptor-1 (PAR-1), plays a key role in exerting this function during melanoma progression. PAR-1 and its activating factors, which are expressed on tumor cells and the surrounding stroma, induce not only coagulation but also cell signaling, which promotes the metastatic phenotype. Several adhesion molecules, cytokines, growth factors, and proteases have recently been identified as downstream targets of PAR-1 and have been shown to modulate interactions between tumor cells and the microenvironment in the process of melanoma growth and metastasis. Inhibiting such interactions by targeting PAR-1 could potentially be a useful therapeutic modality for melanoma patients. ©2011 AACR.

  4. Application of passive auto catalytic recombiner (PAR) for BWR plants in Japan

    International Nuclear Information System (INIS)

    Kobayashi, K.; Murano, K.; Yamanari, S.; Yamamoto, Y.

    2001-01-01

    The passive auto-catalytic recombiner (PAR), which can recombine flammable gases such as hydrogen and oxygen with each other to avoid an explosion in case of a loss-of-coolant accident (LOCA), installed in the primary containment vessel does not require a power supply or dynamic equipment, while the existing flammability gas control system (FCS) of most BWRs as an outer loop of the primary containment vessel needs them to make flammable gases circulate through blowers and heaters in the system. PAR offers a number of advantages over existing FCS, such as high reliability, low cost due to much smaller amount of materials needed, good maintainability, good operability in case of a LOCA, and smaller space for installation. An experimental study has been carried out for the purpose of solving the problems of applying PAR to Japanese BWR plants instead of existing FCS, in which we grasped the basic characteristics of PAR. (author)

  5. ParTIES: a toolbox for Paramecium interspersed DNA elimination studies.

    Science.gov (United States)

    Denby Wilkes, Cyril; Arnaiz, Olivier; Sperling, Linda

    2016-02-15

    Developmental DNA elimination occurs in a wide variety of multicellular organisms, but ciliates are the only single-celled eukaryotes in which this phenomenon has been reported. Despite considerable interest in ciliates as models for DNA elimination, no standard methods for identification and characterization of the eliminated sequences are currently available. We present the Paramecium Toolbox for Interspersed DNA Elimination Studies (ParTIES), designed for Paramecium species, that (i) identifies eliminated sequences, (ii) measures their presence in a sequencing sample and (iii) detects rare elimination polymorphisms. ParTIES is multi-threaded Perl software available at https://github.com/oarnaiz/ParTIES. ParTIES is distributed under the GNU General Public Licence v3. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Effects of solar PAR and UV radiation on tropical biofouling communities

    KAUST Repository

    Dobretsov, SV; Gosselin, L; Qian, P

    2010-01-01

    We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum

  7. uPAR Expression Pattern in Patients with Urothelial Carcinoma of the Bladder

    DEFF Research Database (Denmark)

    Dohn, Line Hammer; Pappot, Helle; Iversen, Benedikte Richter

    2015-01-01

    The objective of the present study was to confirm the expression and localisation pattern of the urokinase-type plasminogen activator receptor (uPAR) focusing on its possible clinical relevance in patients with urothelial neoplasia of the bladder. uPAR is a central molecule in tissue remodelling...... during cancer invasion and metastasis and is an established prognostic marker in various cancer diseases other than bladder cancer. Formalin-fixed and paraffin-embedded tumour-tissue blocks from 186 patients treated with radical cystectomy were analysed. uPAR expression was scored as either negative...... or positive as well as by the actual score. Separate scores were obtained for cancer cells, macrophages and myofibroblasts at the invasive front and in tumour core. We were able to confirm, in an independent patient cohort, the tissue expression and localisation pattern of uPAR as investigated...

  8. Contamination des eaux de puits traditionnels par les nitrates sur le ...

    African Journals Online (AJOL)

    SARAH

    30 juin 2014 ... Objectif : La contamination des eaux souterraines par les nitrates est un ... Methodology and Results: the origin of nitrate water from traditional wells of Lobo's watershed was ...... 12 water supply wells, Yucatan, Mexico.

  9. Dual-detection confocal fluorescence microscopy: fluorescence axial imaging without axial scanning.

    Science.gov (United States)

    Lee, Dong-Ryoung; Kim, Young-Duk; Gweon, Dae-Gab; Yoo, Hongki

    2013-07-29

    We propose a new method for high-speed, three-dimensional (3-D) fluorescence imaging, which we refer to as dual-detection confocal fluorescence microscopy (DDCFM). In contrast to conventional beam-scanning confocal fluorescence microscopy, where the focal spot must be scanned either optically or mechanically over a sample volume to reconstruct a 3-D image, DDCFM can obtain the depth of a fluorescent emitter without depth scanning. DDCFM comprises two photodetectors, each with a pinhole of different size, in the confocal detection system. Axial information on fluorescent emitters can be measured by the axial response curve through the ratio of intensity signals. DDCFM can rapidly acquire a 3-D fluorescent image from a single two-dimensional scan with less phototoxicity and photobleaching than confocal fluorescence microscopy because no mechanical depth scans are needed. We demonstrated the feasibility of the proposed method by phantom studies.

  10. ParFit: A Python-Based Object-Oriented Program for Fitting Molecular Mechanics Parameters to ab Initio Data.

    Science.gov (United States)

    Zahariev, Federico; De Silva, Nuwan; Gordon, Mark S; Windus, Theresa L; Dick-Perez, Marilu

    2017-03-27

    A newly created object-oriented program for automating the process of fitting molecular-mechanics parameters to ab initio data, termed ParFit, is presented. ParFit uses a hybrid of deterministic and stochastic genetic algorithms. ParFit can simultaneously handle several molecular-mechanics parameters in multiple molecules and can also apply symmetric and antisymmetric constraints on the optimized parameters. The simultaneous handling of several molecules enhances the transferability of the fitted parameters. ParFit is written in Python, uses a rich set of standard and nonstandard Python libraries, and can be run in parallel on multicore computer systems. As an example, a series of phosphine oxides, important for metal extraction chemistry, are parametrized using ParFit. ParFit is in an open source program available for free on GitHub ( https://github.com/fzahari/ParFit ).

  11. Infection par le VIH chez les patientes atteintes de cancer du sein en ...

    African Journals Online (AJOL)

    L'objectif était de déterminer la prévalence de l'infection à VIH chez les patientes atteintes de cancer du sein et de comparer les caractéristiques anatomocliques et thérapeutiques de ces cancers du sein par rapports aux patientes non infectées par le VIH. Il s'agissait d'une étude rétrospective et analytique comparant les ...

  12. Etude par simulation hil des performances d'un statcom pour la ...

    African Journals Online (AJOL)

    Ce travail présente l'étude par simulation Hardware In the Loop (HIL) des performances d'un STATCOM pour la stabilisation de la tension délivrée par une génératrice asynchrone triphasée auto excitée dans un réseau autonome. Nous avons combiné l'utilisation du logiciel de simulation LABVIEW et la carte ARDUINO ...

  13. The superoxide scavenger TEMPOL induces urokinase receptor (uPAR expression in human prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Francis Joseph

    2006-06-01

    Full Text Available Abstract There is little understanding of the effect that reactive oxygen metabolites have on cellular behavior during the processes of invasion and metastasis. These oxygen metabolites could interact with a number of targets modulating their function such as enzymes involved in basement membrane dissolution, adhesion molecules involved in motility or receptors involved in proliferation. We investigated the effect of increased scavenging of superoxide anions on the expression of the urokinase receptor (uPAR in PC-3M human prostate cancer cells. Urokinase receptor is a GPI-linked cell surface molecule which mediates multiple functions including adhesion, proliferation and pericellular proteolysis. Addition of the superoxide scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPOL to PC-3M cultures stimulated expression of uPAR protein peaking between 48 and 72 hours. Cell surface expression of the uPAR was also increased. Surprisingly, uPAR transcript levels increased only slightly and this mild increase did not coincide with the striking degree of protein increase. This disparity indicates that the TEMPOL effect on uPAR occurs through a post-transcriptional mechanism. TEMPOL presence in PC-3M cultures reduced intracellular superoxide-type species by 75% as assayed by NBT dye conversion; however this reduction significantly diminished within hours following TEMPOL removal. The time gap between TEMPOL treatment and peak uPAR protein expression suggests that reduction of reactive oxygen metabolites in prostate cancer cells initiates a multistep pathway which requires several hours to culminate in uPAR induction. These findings reveal a novel pathway for uPAR regulation involving reactive oxygens such as superoxide anion.

  14. Compression robuste du signal par la transformée avec les B ...

    African Journals Online (AJOL)

    Par contre, elle diminue de façon considérable pour les b-splincs et les paquets dbndelcttes de Haar. Du point de vue entropie, la compression par bfsplines est bonne que celle de la TCD. Nous donnons ci-dessous un tableau récapitulatif des résultats de quelques méthodes utilisées pour deux signaux EMG. Le facteur de ...

  15. SuPAR predicts postoperative complications and mortality in patients with asymptomatic aortic stenosis

    DEFF Research Database (Denmark)

    Hodges, Gethin W; Bang, Casper N; Eugen-Olsen, Jesper

    2018-01-01

    complications with a HR of 2.7 (95% CI 1.5 to 5.1, P=0.002), per doubling in suPAR. After adjusting for the European System for Cardiac Operative Risk Evaluation or Society of Thoracic Surgeons risk score, suPAR remained associated with postoperative mortality with a HR 3.2 (95% CI 1.2 to 8.6, P=0.025) and 2...

  16. Ultrafast fluorescence of photosynthetic crystals and light-harvesting complexes

    NARCIS (Netherlands)

    Oort, van B.F.

    2008-01-01

    This thesis focuses on the study of photosynthetic pigment protein complexes using time resolved fluorescence techniques. Fluorescence spectroscopy often requires attaching fluorescent labels to the proteins under investigation. With photosynthetic proteins this is not necessary, because these

  17. Formation and de-excitation of hot nuclei in reactions induced by proton beams (475 MeV and 2 GeV) and {sup 3}He beam (2 GeV); Formation et desexcitation des noyaux chauds dans les reactions induites par des faisceaux de protons (475 MeV et 2 GeV) et d`{sup 3}He(2 GeV)

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, X.

    1995-04-01

    We are studying the formation and the de-excitation of hot nuclei created in reactions induced by light high energy projectiles. These reactions, described in a two step model: an intranuclear cascade followed by an evaporation phase, produce nuclei in which the collective modes (compression, rotation, deformation) are weakly excited. By measuring the neutron multiplicities, event by event with ORION, and the light charged particle energies and multiplicities one can evaluate the excitation energy distribution of the nuclei. At the same time, theoretical simulations are carried out using the intranuclear cascade code developed by J. Cugnon and the statistical de-excitation code GEMINI. The good agreement with experimental results indicate that 10% of the p-nucleus interactions lead to temperatures greater than 5 MeV. The observation of the fission of a nucleus with a temperature close to 5 MeV shows that the nucleus behaves as a set of bound nucleons and, that the temperature stability limit is not yet reached. The observed decline of fission probability at high excitation energies is most likely to be correlated to the appearance of an other de-excitation process (evaporation residues emission or multifragmentation) which could not be experimentally detected. Finally, in the last chapter, we briefly present the principle of transmutation for long-lived nuclear waste with a proton accelerator and underline the interest of the present work in such studies. (author). 54 refs., 80 figs., 13 tabs.

  18. Cross section measurements of the processes occurring in the fragmentation of H{sub n}{sup +} (3 {<=} n {<=} 35) hydrogen clusters induced by high speed (60 keV/u) collisions on helium atoms; Mesure des sections efficaces des differents processus intervenant dans la fragmentation d`agregats d`hydrogene H{sub n}{sup +} (3 {<=} n {<=} 35) induite par collision a haute vitesse (60 keV/u) sur un atome d`helium

    Energy Technology Data Exchange (ETDEWEB)

    Louc, Sandrine [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-09-15

    Different processes involved in the fragmentation of ionised hydrogen clusters H{sub 3} + (H{sub 2}){sub (n-3)/2} (n = 5-35) have been studied in the same experiment: the fragmentation of the cluster is induced by the collision with an helium atom at high velocity ({approx_equal} c/100). The collision is realised in reversed kinematic - clusters are accelerated - which allows the detection of neutral and charged fragments. The different channels of fragmentation are identified by using coincidence techniques. For all the cluster sizes studied the capture cross sections of one electron of the target by the cluster is equal to the capture cross section of the H{sub 3}{sup +} ion. In the same way, the dissociation cross section of the H{sub 3}{sup +} core of the cluster does not depend on cluster size. These fragmentation processes are due to the interaction of H{sub 3}{sup +} core of the cluster and the helium atom without ionization of another component of the cluster. On the contrary, the cross sections of loss of one, two and three molecules by the cluster and the dissociation cross section of the cluster in all its molecular components depends strongly on the cluster size. This dependence is different from the one measured for the metastable decay of the cluster. Thus, the process of loss of molecules induced by a collision should correspond to a different dissociation mechanism. In regard of the singularities observed for the size dependence, the H{sub 9}{sup +}, H{sub 15}{sup +}, H{sub 19}{sup +} and H{sub 29}{sup +} clusters could be the `core` of the biggest clusters. These observation are in agreement with the size effects of smaller magnitude observed for the dissociation cross section (all the processes). The values of the cross section for the process of at least one ionization of the cluster indicate that about 80% of the fragmentation events result from this process. (author) 114 refs., 74 figs., 9 tabs.

  19. Potential interest to combine an intensity modulated conformal radiotherapy (I.M.C.R.T.) with a daily repositioning on intra-prostate implants to reduce sexual toxicity induced by exclusive irradiation of prostate cancers; Interets potentiels de combiner une radiotherapie de conformation avec modulation d'intensite (RCMI) avec un repositionnement journalier sur implants intraprostatiques pour reduire la toxicite sexuelle induite par l'irradiation exclusive des cancers de prostate

    Energy Technology Data Exchange (ETDEWEB)

    Chapet, O.; Sotton, M.P.; Vial, L.; Belliere, A.; Ardiet, J.M.; Mornex, F.; Sentenac, I.; Romestaing, P. [Centre Hospitalier Lyon-Sud, Dept. de Radiotherapie-oncologie, 69 - Pierre-Benite (France); Bouffard, J. [Centre Hospitalier Lyon-Sud, Service de Radiologie, 69 - Pierre-Benite (France)

    2007-11-15

    A reduction in margins defining the forecast target volume thanks to a daily repositioning on intra prostate implants would reduce the doses delivered to the penis bulb, corpora cavernosa penis and a. pudendae internae left and right. An optimization of the I.M.C.R.T. on the same anatomical structures amplifies this earnings. The combination of the two could improve the sexual preservation and be proposed for patients with favourable stage prostate cancer. A study of Phase 2 begins soon. (N.C.)

  20. Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV; Mesures de taux de production d'elements gazeux et volatiles lors de reactions induites par des protons de 1 et 1,4 GeV sur des cibles epaisses de plomb et plomb-bismuth liquides

    Energy Technology Data Exchange (ETDEWEB)

    Tall, Y

    2008-03-15

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

  1. Fluorescent S-layer fusion proteins

    International Nuclear Information System (INIS)

    Kainz, B.

    2010-01-01

    This work describes the construction and characterisation of fluorescent S-layer fusion proteins used as building blocks for the fabrication of nanostructured monomolecular biocoatings on silica particles with defined fluorescence properties. The S-layer protein SgsE of Geobacillus stearothermophilus NRS 2004/3a was fused with the pH-dependant cyan, green and yellow variant of the green fluorescent protein (GFP) and the red fluorescent protein mRFP1. These fluorescent S-layer fusion proteins, acting as scaffold and optical sensing element simultaneously, were able to reassemble in solution and on silica particles forming 2D nanostructures with p2 lattice symmetry (a=11 ±0.5 nm, b=14 ±0.4 nm, g=80 ±1 o ). The pH-dependant fluorescence behaviour was studied with fluorimetry, confocal microscopy and flow cytometry. These fluorescent S-layer fusion proteins can be used as pH-sensor. 50% of the fluorescence intensity decreases at their calculated pKa values (pH6 - pH5). The fluorescence intensity of the GFP variants vanished completely between pH4 and pH3 whereas the chromophore of the red protein mRFP1 was only slightly affected in acidic conditions. At the isoelectric point of the S-layer coated silica particles (pH4.6 ±0.2) an increase in particle aggregation was detected by flow cytometry. The cyan and yellow fluorescent proteins were chosen to create a bi-fluorescent S-layer tandem fusion protein with the possibility for resonance energy transfer (FRET). A transfer efficiency of 20% and a molecular distance between the donor (ECFP) and acceptor (YFP) chromophores of around 6.2 nm could be shown. This bi-fluorescent ECFP-SgsE-YFP tandem fusion protein was able to reassemble on solid surfaces. The remarkable combination of fluorescence and self-assembly and the design of bi-functional S-layer tandem fusion protein matrices makes them to a promising tool in nanobiotechnology. (author) [de

  2. Fluorescence imaging of soybean flavonol isolines

    Science.gov (United States)

    Kim, Moon S.; Lee, Edward H.; Mulchi, Charles L.; McMurtrey, James E., III; Chappelle, Emmett W.; Rowland, Randy A.

    1998-07-01

    Experiments were conducted to characterize the fluorescence emission of leaves from four soybean ('Harosoy') plants containing different concentrations of flavonols (kaempferol glycosides). The investigation utilized genetically mutated soybean flavonol isolines grown in a constant environment, thus limiting factors known to affect fluorescence emission characteristics other than different kaempferol glycosides concentrations. Flavonol isolines included OX922, OX941, OX942, OX944. The first two isolines contain kaempferol (K) glycosides; K3, K6, and K9, and the latter two did not have K3, K6, and K9. A fluorescence imaging system (FIS) was used to characterize steady state florescence images of the sample leaves measured at wavelengths centered at 450, 550, 680, and 740 nm with an excitation at 360 nm. Images taken with FIS greatly complement non-imaging fluorescence measurements by characterizing the spatial variation of fluorescence within leaves. We also acquired fluorescence emission spectra to characterize spectral features of the soybean flavonol isolines. The emission spectral shape of the fluorescence emission characteristics were not significantly different between the soybeans that contain kaempferol glycosides and the ones that do not contain kaempferol glycosides. Typical emission maxima of green vegetation in the blue, green, red, and far-red bands were noticed in all four soybean isolines. However, plants containing kaempferol glycosides, OX922 and OX941 had significantly lower intensities throughout the wavelength regions. These results imply that fluorescence emission intensities in the fluorescence emission bands studied are significantly affected by the presence and absence of kaempferol glycosides concentrations (UV radiation screening compounds). Pure kaempferol glycoside dissolved in solution show minimal fluorescence emission when excited with the absorption maximum radiation at 365 nm. However, a broad band emission can be seen in the green

  3. Fluorescence and Docking Studies of the Interaction between Human Serum Albumin and Pheophytin

    Directory of Open Access Journals (Sweden)

    Otávio Augusto Chaves

    2015-10-01

    Full Text Available In the North of Brazil (Pará and Amazonas states the leaves of the plant Talinum triangulare (popular: cariru replace spinach as food. From a phytochemical point of view, they are rich in compounds of the group of pheophytins. These substances, related to chlorophyll, have photophysical properties that give them potential application in photodynamic therapy. Human serum albumin (HSA is one of the main endogenous vehicles for biodistribution of molecules by blood plasma. Association constants and thermodynamic parameters for the interaction of HSA with pheophytin from Talinum triangulare were studied by UV-Vis absorption, fluorescence techniques, and molecular modeling (docking. Fluorescence quenching of the HSA’s internal fluorophore (tryptophan at temperatures 296 K, 303 K, and 310 K, resulted in values for the association constants of the order of 104 L∙mol−1, indicating a moderate interaction between the compound and the albumin. The negative values of ΔG° indicate a spontaneous process; ΔH° = 15.5 kJ∙mol−1 indicates an endothermic process of association and ΔS° = 0.145 kJ∙mol−1∙K−1 shows that the interaction between HSA and pheophytin occurs mainly by hydrophobic factors. The observed Trp fluorescence quenching is static: there is initial non-fluorescent association, in the ground state, HSA:Pheophytin. Possible solution obtained by a molecular docking study suggests that pheophytin is able to interact with HSA by means of hydrogen bonds with three lysine and one arginine residues, whereas the phytyl group is inserted in a hydrophobic pocket, close to Trp-214.

  4. Superresolution imaging in live Caulobacter crescentus cells using photoswitchable enhanced yellow fluorescent protein

    Science.gov (United States)

    Biteen, Julie S.; Thompson, Michael A.; Tselentis, Nicole K.; Shapiro, Lucy; Moerner, W. E.

    2009-02-01

    Recently, photoactivation and photoswitching were used to control single-molecule fluorescent labels and produce images of cellular structures beyond the optical diffraction limit (e.g., PALM, FPALM, and STORM). While previous live-cell studies relied on sophisticated photoactivatable fluorescent proteins, we show in the present work that superresolution imaging can be performed with fusions to the commonly used fluorescent protein EYFP. Rather than being photoactivated, however, EYFP can be reactivated with violet light after apparent photobleaching. In each cycle after initial imaging, only a sparse subset fluorophores is reactivated and localized, and the final image is then generated from the measured single-molecule positions. Because these methods are based on the imaging nanometer-sized single-molecule emitters and on the use of an active control mechanism to produce sparse sub-ensembles, we suggest the phrase "Single-Molecule Active-Control Microscopy" (SMACM) as an inclusive term for this general imaging strategy. In this paper, we address limitations arising from physiologically imposed upper boundaries on the fluorophore concentration by employing dark time-lapse periods to allow single-molecule motions to fill in filamentous structures, increasing the effective labeling concentration while localizing each emitter at most once per resolution-limited spot. We image cell-cycle-dependent superstructures of the bacterial actin protein MreB in live Caulobacter crescentus cells with sub-40-nm resolution for the first time. Furthermore, we quantify the reactivation quantum yield of EYFP, and find this to be 1.6 x 10-6, on par with conventional photoswitchable fluorescent proteins like Dronpa. These studies show that EYFP is a useful emitter for in vivo superresolution imaging of intracellular structures in bacterial cells.

  5. Hep par-1: a novel immunohistochemical marker for differentiating hepatocellular carcinoma from metastatic carcinoma

    International Nuclear Information System (INIS)

    Hanif, R.

    2014-01-01

    To evaluate the diagnostic utility of Hep par-1 in differentiating hepatocellular carcinoma from metastatic carcinoma taking histopathology as a gold standard. Study Design: Comparative cross-sectional study. Place and Duration of Study: Pathology Department, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, from April 2007 to February 2008. Methodology: Hep par-1 immunohistochemical stain was performed on 60 cases of liver carcinoma, 30 cases each of metastatic and hepatocellular carcinoma. Information regarding patient age, gender, sign and symptoms, radiographic findings, histological grade of tumour, and expression of Hep par-1 on hepatocellular and metastatic carcinoma were recorded on proforma sheet. Sensitivity, specificity, positive and negative predictive values, and accuracy of Hep par-1 were calculated using the formulas. Results: Hep par-1 expression was noted in 25 out of 30 cases of hepatocellular carcinoma (83%). Out of 30 cases of metastatic carcinoma, only one case expressed staining in < 5% tumour cells and remaining 29 cases showed no reactivity. The age of the patients with hepatocellular carcinoma ranged from 40 to 76 years with a median age of 60.5 years and 40 - 75 years for metastatic carcinomas with a median age of 57.5 years. Conclusion: Hep par-1 is a reliable immunohistochemical marker for cases of hepatocellular carcinoma (HCC). It can be used along with other markers in morphologically difficult cases when differential diagnosis lies between poorly differentiated HCC and metastatic carcinoma of liver. (author)

  6. Par and IR reflectance, transmittance, and absorptance of four crop canopies

    International Nuclear Information System (INIS)

    Wanjura, D.F.; Hatfield, J.L.

    1986-01-01

    Reflectance, transmittance and absorptance of electromagnetic radiation by cotton, soybeans, grain sorghum, and sunflower was measured at three growth stages in two wavebands (PAR: 0.4 to 0.7 pun and IR: 0.7 to 1.1 yim). As leaf area increased in each crop there were increases in IR reflectance and PAR absorptance and decreases in PAR reflectance and both PAR and IR transmittance. IR radiation was concentrated at the soil surface between rows by reflectance from the sides of canopies when crop cover was less than 80%. Across all crops one parameter, leaf overlap index, explained 81 and 71% of the PAR reflectance and another, crop cover, explained 86 and 94% of IR reflectance from rows and interrows, respectively. Attenuation of PAR radiation through the canopies of cotton and sunflower was similar (K = 0.62 and 0.67) but different from that of soybeans and grain sorghum (K = 0.46 and 0.43) which were the same

  7. Numerical analysis of the influence of PAR unit elevation within a vessel on its performance

    International Nuclear Information System (INIS)

    Kotouč, Miroslav

    2011-01-01

    On the basis of successful validation of the MELCOR code on several experiments from the international OECD/NEA programme THAI, a numerical parametric study has been conducted at NRI Řež evaluating the influence of PAR's vertical position within a vessel on its performance. Simulations were carried out for an Areva PAR unit which was considered to be placed at 5 different elevations in the THAI test vessel, the sixth simulation comprised a model of blower, simulating thus forced convection. The initial conditions were those of the THAI HR-12 test, which was characterized by steam-saturated atmosphere at elevated pressure and temperature. The results show that the overall hydrogen mass recombined monotonically decreases with PAR elevation. This behavior is due to hot, light and hydrogen-lean plume, coming out from the PAR outlet, which, due to buoyancy forces, eventually fills the upper part of the vessel and prevents thus the PAR unit from efficient operation (if the latter is placed near the top). It was also demonstrated that the effect of forced convection is favorable since it breaks the gas stratification and increases thus hydrogen concentration at the PAR inlet. (author)

  8. Factor Xa stimulates fibroblast procollagen production, proliferation, and calcium signaling via PAR1 activation

    International Nuclear Information System (INIS)

    Blanc-Brude, Olivier P.; Archer, Fabienne; Leoni, Patricia; Derian, Claudia; Bolsover, Steven; Laurent, Geoffrey J.; Chambers, Rachel C.

    2005-01-01

    Fibroblast proliferation and procollagen production are central features of tissue repair and fibrosis. In addition to its role in blood clotting, the coagulation cascade proteinase thrombin can contribute to tissue repair by stimulating fibroblasts via proteolytic activation of proteinase-activated receptor-1 (PAR 1 ). During hemostasis, the coagulation cascade proteinase factor X is converted into factor Xa. We have previously shown that factor Xa upregulates fibroblast proliferation via production of autocrine PDGF. In this study, we further examined the effects of factor Xa on fibroblast function and aimed to identify its signaling receptor. We showed that factor Xa stimulates procollagen promoter activity and protein production by human and mouse fibroblasts. This effect was independent of PDGF and thrombin production, but dependent on factor Xa proteolytic activity. We also showed that PAR 1 -deficient mouse fibroblasts did not upregulate procollagen production, mobilize cytosolic calcium, or proliferate in response to factor Xa. Desensitization techniques and PAR 1 -specific agonists and inhibitors were used to demonstrate that PAR 1 mediates factor Xa signaling in human fibroblasts. This is the first report that factor Xa stimulates extracellular matrix production. In contrast with endothelial cells and vascular smooth muscle cells, fibroblasts appear to be the only cell type in which the effects of factor Xa are mediated mainly via PAR 1 and not PAR 2 . These findings are critical for our understanding of tissue repair and fibrotic mechanisms, and for the design of novel approaches to inhibit the profibrotic effects of the coagulation cascade without compromising blood hemostasis

  9. Elevated soluble urokinase plasminogen activator receptor (suPAR) predicts mortality in Staphylococcus aureus bacteremia

    DEFF Research Database (Denmark)

    Mölkänen, T; Ruotsalainen, E; Thorball, C W

    2011-01-01

    The soluble form of urokinase-type plasminogen activator receptor (suPAR) is a new inflammatory marker. High suPAR levels have been shown to associate with mortality in cancer and in chronic infections like HIV and tuberculosis, but reports on the role of suPAR in acute bacteremic infections...... are scarce. To elucidate the role of suPAR in a common bacteremic infection, the serum suPAR levels in 59 patients with Staphylococcus aureus bacteremia (SAB) were measured using the suPARnostic ELISA assay and associations to 1-month mortality and with deep infection focus were analyzed. On day three, after...... the first positive blood culture for S. aureus, suPAR levels were higher in 19 fatalities (median 12.3; range 5.7-64.6 ng/mL) than in 40 survivors (median 8.4; range 3.7-17.6 ng/mL, p = 0.002). This difference persisted for 10 days. The presence of deep infection focus was not associated with elevated su...

  10. Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR).

    Science.gov (United States)

    Burnett, Scott E; Hawkey, Diane E; Turner, Christy G

    2010-02-01

    The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five-grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian-derived populations exhibited the highest MxPAR frequencies while Indo-European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. 2009 Wiley-Liss, Inc.

  11. Examining relational empowerment for elementary school students in a yPAR program.

    Science.gov (United States)

    Langhout, Regina Day; Collins, Charles; Ellison, Erin Rose

    2014-06-01

    This paper joins relational empowerment, youth empowerment, and Bridging Multiple Worlds frameworks to examine forms of relational empowerment for children in two intermediary institutions-school and a youth participatory action research after-school program (yPAR ASP). Participants were twelve children, most of whom were Latina/o and from im/migrant families, enrolled in a yPAR ASP for 2 years. A mixed-method approach was utilized; we analyzed children's interviews, self-defined goals, and their social networks to examine their experiences of relational empowerment. We conclude that children experienced each of the five relational empowerment factors-collaborative competence, bridging social divisions, facilitating others' empowerment, mobilizing networks, and passing on a legacy-in the yPAR ASP setting, and some factors in school. These experiences, however, were more pronounced in the yPAR ASP setting. Additionally, social network analyses revealed that a small but meaningful percentage of actors bridged worlds, especially home and family, but by year 2, also school and the yPAR ASP. Finally, most helpers for school-based goals came from school, but a sizable number came from family, friends, and home worlds, and by year 2, also came from the yPAR ASP. Implications range from theoretical to methodological development, including the use of social network analysis as a tool to descriptively examine relational power in context.

  12. Ultraviolet Radiation Emissions and Illuminance in Different Brands of Compact Fluorescent Lamps

    Directory of Open Access Journals (Sweden)

    Shahram Safari

    2015-01-01

    Full Text Available Introduction. Replacing incandescent lamps with compact fluorescent lamps (CFLs, which are three to six times more efficient, is one of the easiest methods to achieve energy efficiency. The present study aimed to evaluate relationships between UV emissions radiated and illuminance CFLs. Material and Methods. This pilot study was conducted on 16 single envelope CFLs. The illuminance and UV irradiance of various types of CFLs are measured on a three-meter long optical bench, using a calibrated lux meter and UV meter, and measurement was done in 10, 25, 50, 100, 150, and 200 cm, in three angles, including 0°, 45°, and 90°, at the ages of 0, 100, and 2000 hours. Result. UVC irradiance was not observed at the distance of 10 cm in all of lamps. The lowest value of UVB irradiance was recorded in Pars Khazar lamp, while the highest value was recorded in Etehad lamps. UVR values measured at different times showed negligible differences; the highest asset value was detected in zero times. One way ANOVA indicated that relationships between UVA irradiance and illuminance were significant (P<0.05. Conclusion. UVB irradiance in most of the lamp in 10 and 25 cm was more than occupational exposure and UVA except for the fact that Pars Khazar 60 watts and Nama Noor 60 watts were less than occupational exposure.

  13. Antinuclear antibodies: clinical significance of fluorescence patterns

    International Nuclear Information System (INIS)

    Cordeiro, S.L.; Habermann, F.; Franco, M.F.

    1981-01-01

    Fifty-four patients with 212 sera positive for antinuclear antibodies (ANA) were studied to: 1) determine the immunofluorescent nuclear staining patterns using Burnham's technique and simplified classification; 2) note the specificity of fluorescence patterns among the various connective tissue diseases; 3) study comparatively the fluorescence paterns employing 5 different antigen substrates; 4) correlate ANA titers and fluorescence patterns with renal involvement in systemic lupus erythematosus (SLE). It was observed: 1) most of the sera gave nonparticulate fluorescent patterns: peripheral, homogeneous, or peripheral-homogeneneous; 2) 55,5% of the patients had LE and most of those sera showed nonparticulate fluorescent patterns; 3) the sera displayed no specificity for any of the following antigen substrates: imprints of human normal spleen, frozen rat liver and kidney sections, frozen mouse kidney sections and perypheral human blood smears; 4) imprints of normal human spleen were the best substrate for accurate identification of fluorescent patterns; 5) sera from SLE patients with renal involvement showed higher ANA titers in relation to patients without renal involvement; both groups of sera gave similar ANA fluorescent patterns. (Author) [pt

  14. L G-2 Scintrex manual.Fluorescence analyzer

    International Nuclear Information System (INIS)

    Pirelli, H.

    1987-01-01

    The Scintrex Fluorescence Analyzer LG-2 selectively detects the presence of certain fluorescent minerals through UV photoluminescence induced and provides quantitative information on its distribution.

  15. Delirio omicidiario condiviso nelle coppie di serial killer / Délire homicidaire partagé par les couples de tueurs en série / Shared psychotic disorder in serial killers acting in pair

    Directory of Open Access Journals (Sweden)

    Mastronardi Vincenzo

    2012-10-01

    Full Text Available Les tueurs en série qui agissent en couple sont très rares d’un point de vue statistique. Le plus souvent, entre les deux membres du couple, un délire commun apparaît progressivement, conduisant ces sujets à réitérer ensemble les passages à l’acte homicidaire.Ce cadre clinique prévoit qu’un individu, défini comme dominant et nommé « Inducteur » ou « Cas primaire », influence un individu plus faible, nommé « Induit », en lui imposant son système délirant. Le plus souvent, le membre du couple le plus faible ne provient pas d’une sous-culture criminelle et ne souffre d’aucun trouble psychiatrique qui justifierait son adhésion aux actions de l’individu dominant. Le syndrome a été décrit pour la première fois par Lasègue et Falret à la fin du XIXème siècle et nommé « folie à deux » ; le DSM-IV TR parle de « trouble psychotique partagé ».Les couples de tueurs en série les plus représentés d’un point de vue statistique sont composées de deux hommes, puis par un homme et une femme et, enfin, par deux femmes.Le lien entre les deux membres de ces couples peut être de type amical, sentimental ou de parenté.Bien que le « Cas primaire » soit dominant dans le couple, il ne faut pas négliger la contribution de l’individu faible au délire homicidaire partagé : en effet, sur la base de la logique particulière d’une relation complémentaire pathologique, les deux acteurs jouent un rôle majeur et fonctionnel à la continuité de la relation. Même l’individu apparemment le plus passif et soumis joue un rôle actif dans la formation du délire homicidaire partagé.Serial killers acting in pair represent an event which is statistically very rare. A sort of common delirium gradually structured between the two members of the pair, brings them to reiterate their homicidal actions.This clinical situation provides that a person described as dominant and called “inducer” or “primary” or

  16. Parijs is een meervoud. Adriaan van Dis en de heruitvinding van de Hollander in Parijs

    NARCIS (Netherlands)

    Koffeman, M.N.; Koffeman, Maaike; Montoya, Alicia C.; Smeets, Marc

    2017-01-01

    Parijs, tot halverwege de 20ste eeuw het onbetwiste centrum van de Europese cultuur, heeft van oudsher een grote aantrekkingskracht uitgeoefend op Nederlandse kunstenaars en schrijvers. Velen van hen verbleven er kortere of langere tijd, op zoek naar internationale erkenning. De vrijere seksuele moraal

  17. Enhancement of uranyl fluorescence using trimesic acid: Ligand sensitization and co-fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Maji, S. [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.in [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2011-09-15

    Trimesic acid (TMA) was shown to sensitize and enhance uranyl fluorescence in aqueous medium, with the enhancement being a maximum at pH 5.0. Fluorescence spectra and lifetime data together suggest that TMA complexes with uranyl (UO{sub 2}{sup 2+}). The fluorescence of UO{sub 2}{sup 2+} in its acid complex is further enhanced by more than two orders of magnitude following the addition of Y{sup 3+}; a process referred to as co-fluorescence, leading to the possibility of detecting uranium at sub ng/mL level. The present study demonstrates, for the first time, fluorescence enhancement of the uranyl species due to co-fluorescence. - Highlights: > Trimesic acid was shown to sensitize and enhance the fluorescence of uranium in aqueous medium. > This ligand also exhibited co-fluorescence of uranium with Y{sup 3+}. > To the best of our knowledge this is the first report of co-fluorescence in uranium. > The enhancement of uranium fluorescence, resulted in detection limits in the ng/mL regime.

  18. Effects of Depilation-Induced Skin Pigmentation and Diet-Induced Fluorescence on In Vivo Fluorescence Imaging

    OpenAIRE

    Kwon, Sunkuk; Sevick-Muraca, Eva M.

    2017-01-01

    Near-infrared fluorescence imaging (NIRFI) and far-red fluorescence imaging (FRFI) were used to investigate effects of depilation-induced skin pigmentation and diet-induced background fluorescence on fluorescent signal amplitude and lymphatic contraction frequency in C57BL6 mice. Far-red fluorescent signal amplitude, but not frequency, was affected by diet-induced fluorescence, which was removed by feeding the mice an alfalfa-free diet, and skin pigmentation further impacted the amplitude mea...

  19. Fluorescence detection system for microfluidic droplets

    Science.gov (United States)

    Chen, Binyu; Han, Xiaoming; Su, Zhen; Liu, Quanjun

    2018-05-01

    In microfluidic detection technology, because of the universality of optical methods in laboratory, optical detection is an attractive solution for microfluidic chip laboratory equipment. In addition, the equipment with high stability and low cost can be realized by integrating appropriate optical detection technology on the chip. This paper reports a detection system for microfluidic droplets. Photomultiplier tubes (PMT) is used as a detection device to improve the sensitivity of detection. This system improves the signal to noise ratio by software filtering and spatial filter. The fluorescence intensity is proportional to the concentration of the fluorescence and intensity of the laser. The fluorescence micro droplets of different concentrations can be distinguished by this system.

  20. Ratiometric fluorescent nanoparticles for sensing temperature

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hong-Shang, E-mail: hillphs@yahoo.com.cn; Huang, Shi-Hua [Beijing Jiaotong University, Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology (China); Wolfbeis, Otto S. [University of Regensburg, Institute of Analytical Chemistry, Chemo- and Biosensors (Germany)

    2010-10-15

    A ratiometric type of fluorescent nanoparticle was prepared via an encapsulation-reprecipitation method. By introducing an alkoxysilanized dye as a reference, the nanoparticles (NPs) give both a green and a red fluorescence under one single-wavelength excitation. The resulted ratiometric fluorescence is found to be highly temperature-dependent in the physiological range (25-45 {sup o}C), with an intensity temperature sensitivity of -4.0%/{sup o}C. Given the small size (20-30 nm in diameter) and biocompatible nature (silica out layer), such kind of NPs were very promising as temperature nanosensors for cellular sensing and imaging.

  1. High yield fabrication of fluorescent nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Boudou, Jean-Paul; Curmi, Patrick A [Structure and Activity of Normal and Pathological Biomolecules-INSERM/UEVE U829, Universite d' Evry-Val d' Essonne, Batiment Maupertuis, Rue du pere Andre Jarlan, F-91025 Evry (France); Jelezko, Fedor; Wrachtrup, Joerg; Balasubramanian, Gopalakrischnan; Reuter, Rolf [3.Physikalisches Institut, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany); Aubert, Pascal [Nanometric Media Laboratory, Universite d' Evry-Val d' Essonne, Batiment Maupertuis, Rue du pere Andre Jarlan, F-91025 Evry (France); Sennour, Mohamed; Thorel, Alain [Centre des Materiaux, Mines Paris, ParisTech, BP 87, F-91000 Evry (France); Gaffet, Eric [Nanomaterials Research Group-UMR 5060, CNRS, UTBM, Site de Sevenans, F-90010 Belfort (France)], E-mail: jpb.cnrs@free.fr, E-mail: pcurmi@univ-evry.fr, E-mail: f.jelezko@physik.uni-stuttgart.de

    2009-06-10

    A new fabrication method to produce homogeneously fluorescent nanodiamonds with high yields is described. The powder obtained by high energy ball milling of fluorescent high pressure, high temperature diamond microcrystals was converted in a pure concentrated aqueous colloidal dispersion of highly crystalline ultrasmall nanoparticles with a mean size less than or equal to 10 nm. The whole fabrication yield of colloidal quasi-spherical nanodiamonds was several orders of magnitude higher than those previously reported starting from microdiamonds. The results open up avenues for the industrial cost-effective production of fluorescent nanodiamonds with well-controlled properties.

  2. High yield fabrication of fluorescent nanodiamonds

    International Nuclear Information System (INIS)

    Boudou, Jean-Paul; Curmi, Patrick A; Jelezko, Fedor; Wrachtrup, Joerg; Balasubramanian, Gopalakrischnan; Reuter, Rolf; Aubert, Pascal; Sennour, Mohamed; Thorel, Alain; Gaffet, Eric

    2009-01-01

    A new fabrication method to produce homogeneously fluorescent nanodiamonds with high yields is described. The powder obtained by high energy ball milling of fluorescent high pressure, high temperature diamond microcrystals was converted in a pure concentrated aqueous colloidal dispersion of highly crystalline ultrasmall nanoparticles with a mean size less than or equal to 10 nm. The whole fabrication yield of colloidal quasi-spherical nanodiamonds was several orders of magnitude higher than those previously reported starting from microdiamonds. The results open up avenues for the industrial cost-effective production of fluorescent nanodiamonds with well-controlled properties.

  3. Experimental station for gas phase fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Stankiewicz, M.; Garcia, E. Melero; Ruiz, J. Alvarez; Erman, P.; Hatherly, P.A.; Kivimaeki, A.; Rachlew, E.; Rius i Riu, J.

    2004-01-01

    The details of an experimental setup for gas phase atomic and molecular fluorescence measurements using synchrotron radiation are described in this article. The most significant part of the apparatus is an optical arrangement, which allows for simultaneous measurements of dispersed as well as total fluorescence intensity using an effusive gas jet and an inbuilt gas cell assembled in a convenient plug and measure configuration. The first measurements concerning fluorescence of the N 2 molecule around the N 1s edge obtained with this setup are presented

  4. Modeling post-wildfire hydrological processes with ParFlow

    Science.gov (United States)

    Escobar, I. S.; Lopez, S. R.; Kinoshita, A. M.

    2017-12-01

    Wildfires alter the natural processes within a watershed, such as surface runoff, evapotranspiration rates, and subsurface water storage. Post-fire hydrologic models are typically one-dimensional, empirically-based models or two-dimensional, conceptually-based models with lumped parameter distributions. These models are useful for modeling and predictions at the watershed outlet; however, do not provide detailed, distributed hydrologic processes at the point scale within the watershed. This research uses ParFlow, a three-dimensional, distributed hydrologic model to simulate post-fire hydrologic processes by representing the spatial and temporal variability of soil burn severity (via hydrophobicity) and vegetation recovery. Using this approach, we are able to evaluate the change in post-fire water components (surface flow, lateral flow, baseflow, and evapotranspiration). This work builds upon previous field and remote sensing analysis conducted for the 2003 Old Fire Burn in Devil Canyon, located in southern California (USA). This model is initially developed for a hillslope defined by a 500 m by 1000 m lateral extent. The subsurface reaches 12.4 m and is assigned a variable cell thickness to explicitly consider soil burn severity throughout the stages of recovery and vegetation regrowth. We consider four slope and eight hydrophobic layer configurations. Evapotranspiration is used as a proxy for vegetation regrowth and is represented by the satellite-based Simplified Surface Energy Balance (SSEBOP) product. The pre- and post-fire surface runoff, subsurface storage, and surface storage interactions are evaluated at the point scale. Results will be used as a basis for developing and fine-tuning a watershed-scale model. Long-term simulations will advance our understanding of post-fire hydrological partitioning between water balance components and the spatial variability of watershed processes, providing improved guidance for post-fire watershed management. In reference

  5. Simulating fluorescence light-canopy interaction in support of laser-induced fluorescence measurements

    International Nuclear Information System (INIS)

    Rosema, A.; Verhoef, W.; Schroote, J.; Snel, J.F.H.

    1991-01-01

    In the Netherlands an operational field instrument for the measurement of laser induced fluorescence of vegetation (LEAF) is developed. In addition, plant physiological and remote sensing research is done to support this new remote sensing instrument. This paper presents a general introduction on the subject of laser-induced fluorescence, including the relation between chlorophyll fluorescence and photosynthesis, spectral characteristics, and previous research. Also the LEAF system is briefly described. Subsequently, the development of a leaf fluorescence model (KMF) and a canopy fluorescence model (FLSAIL) are reported. With these simulation models a sensitivity study is carried out. Fluorescence of 685 nm appears to be most suitable to obtain information on photosynthesis and stress, but is also influenced by canopy structure. Separation of these two effects is studied

  6. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    Directory of Open Access Journals (Sweden)

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  7. uPA/uPAR system activation drives a glycolytic phenotype in melanoma cells.

    Science.gov (United States)

    Laurenzana, Anna; Chillà, Anastasia; Luciani, Cristina; Peppicelli, Silvia; Biagioni, Alessio; Bianchini, Francesca; Tenedini, Elena; Torre, Eugenio; Mocali, Alessandra; Calorini, Lido; Margheri, Francesca; Fibbi, Gabriella; Del Rosso, Mario

    2017-09-15

    In this manuscript, we show the involvement of the uPA/uPAR system in the regulation of aerobic glycolysis of melanoma cells. uPAR over-expression in human melanoma cells controls an invasive and glycolytic phenotype in normoxic conditions. uPAR down-regulation by siRNA or its uncoupling from integrins, and hence from integrin-linked tyrosine kinase receptors (IL-TKRs), by an antagonist peptide induced a striking inhibition of the PI3K/AKT/mTOR/HIF1α pathway, resulting into impairment of glucose uptake, decrease of several glycolytic enzymes and of PKM2, a checkpoint that controls metabolism of cancer cells. Further, binding of uPA to uPAR regulates expression of molecules that govern cell invasion, including extracellular matrix metallo-proteinases inducer (EMPPRIN) and enolase, a glycolytyc enzyme that also serves as a plasminogen receptor, thus providing a common denominator between tumor metabolism and phenotypic invasive features. Such effects depend on the α5β1-integrin-mediated uPAR connection with EGFR in melanoma cells with engagement of the PI3K-mTOR-HIFα pathway. HIF-1α trans-activates genes whose products mediate tumor invasion and glycolysis, thus providing the common denominator between melanoma metabolism and its invasive features. These findings unveil a unrecognized interaction between the invasion-related uPAR and IL-TKRs in the control of glycolysis and disclose a new pharmacological target (i.e., uPAR/IL-TKRs axis) for the therapy of melanoma. © 2017 UICC.

  8. Lumbar lordosis and pars interarticularis fractures: a case-control study

    International Nuclear Information System (INIS)

    Bugg, William G.; Lewis, Mark; Juette, Arne; Cahir, John G.; Toms, Andoni P.

    2012-01-01

    The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

  9. Lumbar lordosis and pars interarticularis fractures: a case-control study

    Energy Technology Data Exchange (ETDEWEB)

    Bugg, William G; Lewis, Mark; Juette, Arne; Cahir, John G; Toms, Andoni P [Cotman Centre, Norwich Radiology Academy, Norwich, Norfolk (United Kingdom)

    2012-07-15

    The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

  10. Lumbar lordosis and pars interarticularis fractures: a case-control study

    Energy Technology Data Exchange (ETDEWEB)

    Bugg, William G.; Lewis, Mark; Juette, Arne; Cahir, John G.; Toms, Andoni P. [Cotman Centre, Norwich Radiology Academy, Norwich, Norfolk (United Kingdom)

    2012-07-15

    The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

  11. A method for estimating the diffuse attenuation coefficient (KdPAR)from paired temperature sensors

    Science.gov (United States)

    Read, Jordan S.; Rose, Kevin C.; Winslow, Luke A.; Read, Emily K.

    2015-01-01

    A new method for estimating the diffuse attenuation coefficient for photosynthetically active radiation (KdPAR) from paired temperature sensors was derived. We show that during cases where the attenuation of penetrating shortwave solar radiation is the dominant source of temperature changes, time series measurements of water temperatures at multiple depths (z1 and z2) are related to one another by a linear scaling factor (a). KdPAR can then be estimated by the simple equation KdPAR ln(a)/(z2/z1). A suggested workflow is presented that outlines procedures for calculating KdPAR according to this paired temperature sensor (PTS) method. This method is best suited for conditions when radiative temperature gains are large relative to physical noise. These conditions occur frequently on water bodies with low wind and/or high KdPARs but can be used for other types of lakes during time periods of low wind and/or where spatially redundant measurements of temperatures are available. The optimal vertical placement of temperature sensors according to a priori knowledge of KdPAR is also described. This information can be used to inform the design of future sensor deployments using the PTS method or for campaigns where characterizing sub-daily changes in temperatures is important. The PTS method provides a novel method to characterize light attenuation in aquatic ecosystems without expensive radiometric equipment or the user subjectivity inherent in Secchi depth measurements. This method also can enable the estimation of KdPAR at higher frequencies than many manual monitoring programs allow.

  12. RESOLUTION DU PROBLEME DE PREDICTION LINEAIRE PAR LA METHODE ULV. APPLICATION AU SIGNAL FID

    Directory of Open Access Journals (Sweden)

    M KHELIF

    2003-06-01

    Full Text Available Dans le cadre de la spectroscopie RMN, notre objectif est de déterminer le spectre d'absorption du signal de précession libre FID par la méthode de prédiction linéaire (PL. Ceci revient à résoudre le problème de prédiction linéaire en exploitant la méthode de corrélation par l'utilisation de la décomposition en valeurs singulières SVD pour l'inversion de la matrice de corrélation. Or, cette technique est la source d'un certain nombre de problèmes lorsque le signal est noyé dans du bruit. Aussi sera-t-elle coûteuse en temps lorsque les dimensions de la matrice de corrélation sont importantes. Afin de résoudre ce problème, nous exploitons les propriétés d'une nouvelle technique dérivée de la SVD, la décomposition ULV pour minimiser le coût du traitement et assurer une inversion correcte de la matrice de corrélation. Dans ce but, nous déterminons le spectre d'absorption par la technique ULV et nous le comparons avec le spectre déterminé par la SVD et  la FFT. Nous comparons par la suite la qualité des spectres obtenus par rapport au spectre d'absorption idéal  déterminé par FFT.

  13. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  14. Collisional and radiative processes in fluorescent lamps

    International Nuclear Information System (INIS)

    Lister, Graeme G.

    2003-01-01

    Since electrode life is the major limiting factor in operating fluorescent lamps, many lighting companies have introduced 'electrodeless' fluorescent lamps, using inductively coupled discharges. These lamps often operate at much higher power loadings than standard lamps and numerical models have not been successful in reproducing experimental measurements in the parameter ranges of interest. A comprehensive research program was undertaken to study the fundamental physical processes of these discharges, co-funded by the Electric Power Research Institute (EPRI) and OSRAM SYLVANIA under the name of ALITE. The program included experiments and modeling of radiation transport, computations of electron-atom and atom-atom cross sections and the first comprehensive power balance studies of a highly loaded fluorescent lamp. Results from the program and their importance to the understanding of the physics of fluorescent lamps are discussed, with particular emphasis on the important collisional and radiative processes. Comparisons between results of experimental measurements and numerical models are presented

  15. Fluorescent zinc–terpyridine complex containing coordinated ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Zinc peroxo complex; terpyridine complexes; fluorescence ... structure determination 3. Zinc is an essential element for normal function of most .... 63 179; (d) De Silva A P, Gunaratna H Q N, Gunnlaugsson T, Huxley A J M, Mcloy C.

  16. Synthesis and characterization of multicolour fluorescent ...

    Indian Academy of Sciences (India)

    ... of latent fingerprints. The optical and structural characterization of the nanoparticles was carried .... by absorption of phonons from the host matrix [13], the exchange of energy in ... impressions based on the fluorescent properties exhibited by.

  17. Fluorescence of berberine in microheterogeneous systems

    Energy Technology Data Exchange (ETDEWEB)

    Colina, Ariel N.; Díaz, Marta S.; Gutiérrez, María Isela, E-mail: isela@unpata.edu.ar

    2013-12-15

    Spectral properties of the alkaloid berberine were studied in micellar solution and microemulsions based on anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide and nonionic Triton X-100 surfactants. Absorption and fluorescence emission spectra were determined. For screening the influence of type and concentration of micelles on the fluorescence of berberine a 3{sup 2} full factorial design was used. Higher responses were obtained when berberine was dissolved in sodium dodecyl sulfate micelles 0.01 M. Comparative results of fluorescence quantum yields (Φ{sub f}) reveal that the highest values (Φ{sub f}≥0.01) were observed in microemulsions. In the microheterogeneous systems investigated the most probable location of berberine is the micellar interfacial region. -- Highlights: • Spectroscopic propereies of berberine in microheterogeneous media were investigated. • Berberine shows enhanced fluorescence in SDS micelles as compared to water • Berberine is probably located in the interface of the microheterogeneous systems.

  18. Fluorescence of irradiated hydrocarbons. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Gulis, I G; Evdokimenko, V M; Lapkovskii, M P; Petrov, P T; Gulis, I M; Markevich, S V [AN Belorusskoj SSR, Minsk. Inst. Fiziko-Organicheskoj Khimii

    1977-01-01

    A visible fluorescence has been found out in ..gamma..-irradiated aqueous solutions of carbohydrates. Two bands have been distinguished in fluorescence spectra of the irradiated solution of dextran: a short-wave band lambdasub(max)=140 nm (where lambda is a wave length) at lambdasub(..beta..)=380 nm and a long-wave band with lambdasub(max)=540 nm at lambdasub(..beta..)=430 nm. A similar form of the spectrum has been obtained for irradiated solutions of starch, amylopectin, low molecular glucose. It has been concluded that a macromolecule of polysaccharides includes fluorescent centers. A relation between fluorescence and ..cap alpha..-oxiketon groups formed under irradiation has been pointed out.

  19. Excimer fluorescence of liquid crystalline systems

    Science.gov (United States)

    Sakhno, Tamara V.; Khakhel, Oleg A.; Barashkov, Nikolay N.; Korotkova, Irina V.

    1996-04-01

    The method of synchronous scanning fluorescence spectroscopy shows a presence of dimers of pyrene in a polymeric matrix. The results suggest that excimer formation takes place with dimers in liquid crystalline systems.

  20. Fluorescence of berberine in microheterogeneous systems

    International Nuclear Information System (INIS)

    Colina, Ariel N.; Díaz, Marta S.; Gutiérrez, María Isela

    2013-01-01

    Spectral properties of the alkaloid berberine were studied in micellar solution and microemulsions based on anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide and nonionic Triton X-100 surfactants. Absorption and fluorescence emission spectra were determined. For screening the influence of type and concentration of micelles on the fluorescence of berberine a 3 2 full factorial design was used. Higher responses were obtained when berberine was dissolved in sodium dodecyl sulfate micelles 0.01 M. Comparative results of fluorescence quantum yields (Φ f ) reveal that the highest values (Φ f ≥0.01) were observed in microemulsions. In the microheterogeneous systems investigated the most probable location of berberine is the micellar interfacial region. -- Highlights: • Spectroscopic propereies of berberine in microheterogeneous media were investigated. • Berberine shows enhanced fluorescence in SDS micelles as compared to water • Berberine is probably located in the interface of the microheterogeneous systems

  1. Isomerization and fluorescence depolarization of merocyanine 540 ...

    Indian Academy of Sciences (India)

    , ... polymers resemble globular proteins and can encapsulate hydrophobic solutes. ... PAA opens up due to electrostatic repulsion, the fluorescent probe becomes exposed to ... conformational transition of such polymers have been studied by ...

  2. Laser-induced fluorescence imaging of bacteria

    Science.gov (United States)

    Hilton, Peter J.

    1998-12-01

    This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

  3. 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...

  4. Modified Hyperbranched Polymers for Fluorescence Sensing Applications

    Science.gov (United States)

    2012-06-01

    sensors. The HBPs transported the fluorescent groups to the fiber mat surface where they interacted with mercury (Hg(II)) or cytochrome c as the analyte...coworkers (27, 28) have employed fluorescence quenching using a binol-based dendrimer sensor, which exhibited differential sensitivity to enantiomeric...based sensors using HBP-based fluorophores was demonstrated in this report. Low concentrations of fluorophore were transported to the surface of

  5. Identification of a new epitope in uPAR as a target for the cancer therapeutic monoclonal antibody ATN-658, a structural homolog of the uPAR binding integrin CD11b (αM.

    Directory of Open Access Journals (Sweden)

    Xiang Xu

    Full Text Available The urokinase plasminogen activator receptor (uPAR plays a role in tumor progression and has been proposed as a target for the treatment of cancer. We recently described the development of a novel humanized monoclonal antibody that targets uPAR and has anti-tumor activity in multiple xenograft animal tumor models. This antibody, ATN-658, does not inhibit ligand binding (i.e. uPA and vitronectin to uPAR and its mechanism of action remains unclear. As a first step in understanding the anti-tumor activity of ATN-658, we set out to identify the epitope on uPAR to which ATN-658 binds. Guided by comparisons between primate and human uPAR, epitope mapping studies were performed using several orthogonal techniques. Systematic site directed and alanine scanning mutagenesis identified the region of aa 268-275 of uPAR as the epitope for ATN-658. No known function has previously been attributed to this epitope Structural insights into epitope recognition were obtained from structural studies of the Fab fragment of ATN-658 bound to uPAR. The structure shows that the ATN-658 binds to the DIII domain of uPAR, close to the C-terminus of the receptor, corroborating the epitope mapping results. Intriguingly, when bound to uPAR, the complementarity determining region (CDR regions of ATN-658 closely mimic the binding regions of the integrin CD11b (αM, a previously identified uPAR ligand thought to be involved in leukocyte rolling, migration and complement fixation with no known role in tumor progression of solid tumors. These studies reveal a new functional epitope on uPAR involved in tumor progression and demonstrate a previously unrecognized strategy for the therapeutic targeting of uPAR.

  6. Handheld Fluorescence Microscopy based Flow Analyzer.

    Science.gov (United States)

    Saxena, Manish; Jayakumar, Nitin; Gorthi, Sai Siva

    2016-03-01

    Fluorescence microscopy has the intrinsic advantages of favourable contrast characteristics and high degree of specificity. Consequently, it has been a mainstay in modern biological inquiry and clinical diagnostics. Despite its reliable nature, fluorescence based clinical microscopy and diagnostics is a manual, labour intensive and time consuming procedure. The article outlines a cost-effective, high throughput alternative to conventional fluorescence imaging techniques. With system level integration of custom-designed microfluidics and optics, we demonstrate fluorescence microscopy based imaging flow analyzer. Using this system we have imaged more than 2900 FITC labeled fluorescent beads per minute. This demonstrates high-throughput characteristics of our flow analyzer in comparison to conventional fluorescence microscopy. The issue of motion blur at high flow rates limits the achievable throughput in image based flow analyzers. Here we address the issue by computationally deblurring the images and show that this restores the morphological features otherwise affected by motion blur. By further optimizing concentration of the sample solution and flow speeds, along with imaging multiple channels simultaneously, the system is capable of providing throughput of about 480 beads per second.

  7. Magnetic field control of fluorescent polymer nanorods

    International Nuclear Information System (INIS)

    Kim, Taehyung; He, Le; Bardeen, Christopher J; Morales, Jason R; Beyermann, W P

    2011-01-01

    Nanoscale objects that combine high luminescence output with a magnetic response may be useful for probing local environments or manipulating objects on small scales. Ideally, these two properties would not interfere with each other. In this paper, we show that a fluorescent polymer host material can be doped with high concentrations of 20–30 nm diameter magnetic γ-Fe 2 O 3 particles and then formed into 200 nm diameter nanorods using porous anodic alumina oxide templates. Two different polymer hosts are used: the conjugated polymer polydioctylfluorene and also polystyrene doped with the fluorescent dye Lumogen Red. Fluorescence decay measurements show that 14% by weight loading of the γ-Fe 2 O 3 nanoparticles quenches the fluorescence of the polydioctylfluorene by approximately 33%, but the polystyrene/Lumogen Red fluorescence is almost unaffected. The three-dimensional orientation of both types of nanorods can be precisely controlled by the application of a moderate strength (∼0.1 T) external field with sub-second response times. Transmission electron microscope images reveal that the nanoparticles cluster in the polymer matrix, and these clusters may serve both to prevent fluorescence quenching and to generate the magnetic moment that rotates in response to the applied magnetic field.

  8. CFD modelling of hydrogen stratification in enclosures: Model validation and application to PAR performance

    Energy Technology Data Exchange (ETDEWEB)

    Hoyes, J.R., E-mail: james.hoyes@hsl.gsi.gov.uk; Ivings, M.J.

    2016-12-15

    Highlights: • The ability of CFD to predict hydrogen stratification phenomena is investigated. • Contrary to expectation, simulations on tetrahedral meshes under-predict mixing. • Simulations on structured meshes give good agreement with experimental data. • CFD model used to investigate the effects of stratification on PAR performance. • Results show stratification can have a significant effect on PAR performance. - Abstract: Computational Fluid Dynamics (CFD) models are maturing into useful tools for supporting safety analyses. This paper investigates the capabilities of CFD models for predicting hydrogen stratification in a containment vessel using data from the NEA/OECD SETH2 MISTRA experiments. Further simulations are then carried out to illustrate the qualitative effects of hydrogen stratification on the performance of Passive Autocatalytic Recombiner (PAR) units. The MISTRA experiments have well-defined initial and boundary conditions which makes them well suited for use in a validation study. Results are presented for the sensitivity to mesh resolution and mesh type. Whilst the predictions are shown to be largely insensitive to the mesh resolution they are surprisingly sensitive to the mesh type. In particular, tetrahedral meshes are found to induce small unphysical convection currents that result in molecular diffusion and turbulent mixing being under-predicted. This behaviour is not unique to the CFD model used here (ANSYS CFX) and furthermore, it may affect simulations run on other non-aligned meshes (meshes that are not aligned perpendicular to gravity), including non-aligned structured meshes. Following existing best practice guidelines can help to identify potential unphysical predictions, but as an additional precaution consideration should be given to using gravity-aligned meshes for modelling stratified flows. CFD simulations of hydrogen recombination in the Becker Technologies THAI facility are presented with high and low PAR positions

  9. MARK/Par1 Kinase Is Activated Downstream of NMDA Receptors through a PKA-Dependent Mechanism.

    Directory of Open Access Journals (Sweden)

    Laura P Bernard

    Full Text Available The Par1 kinases, also known as microtubule affinity-regulating kinases (MARKs, are important for the establishment of cell polarity from worms to mammals. Dysregulation of these kinases has been implicated in autism, Alzheimer's disease and cancer. Despite their important function in health and disease, it has been unclear how the activity of MARK/Par1 is regulated by signals from cell surface receptors. Here we show that MARK/Par1 is activated downstream of NMDA receptors in primary hippocampal neurons. Further, we show that this activation is dependent on protein kinase A (PKA, through the phosphorylation of Ser431 of Par4/LKB1, the major upstream kinase of MARK/Par1. Together, our data reveal a novel mechanism by which MARK/Par1 is activated at the neuronal synapse.

  10. Increased plasma soluble uPAR level is a risk marker of respiratory cancer in initially cancer-free individuals

    DEFF Research Database (Denmark)

    Langkilde, Anne A; Hansen, Tine Willum; Ladelund, Steen

    2011-01-01

    BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is a stable plasma biomarker associated with inflammation and disease. This study tested the association between suPAR levels and incident respiratory, gastrointestinal or other types of cancer in initially cancer-free individuals...... with respiratory, gastrointestinal and other cancer types, respectively.CONCLUSIONS: Elevated suPAR levels were associated with increased risk of incident respiratory cancer and other types of cancer, but not gastrointestinal cancers, independently of established risk factors, CRP and leukocyte numbers. Impact.......RESULTS: suPAR levels ranged from 0.6-22 ng/ml, and median suPAR level was 4.01 ng/ml. 1 ng/ml increase in baseline suPAR was associated with adjusted hazard ratios (HR) of 1.61 (95% CI: 1.23-2.11, P

  11. Active zone proteins are transported via distinct mechanisms regulated by Par-1 kinase.

    Directory of Open Access Journals (Sweden)

    Kara R Barber

    2017-02-01

    Full Text Available Disruption of synapses underlies a plethora of neurodevelopmental and neurodegenerative disease. Presynaptic specialization called the active zone plays a critical role in the communication with postsynaptic neuron. While the role of many proteins at the active zones in synaptic communication is relatively well studied, very little is known about how these proteins are transported to the synapses. For example, are there distinct mechanisms for the transport of active zone components or are they all transported in the same transport vesicle? Is active zone protein transport regulated? In this report we show that overexpression of Par-1/MARK kinase, a protein whose misregulation has been implicated in Autism spectrum disorders (ASDs and neurodegenerative disorders, lead to a specific block in the transport of an active zone protein component- Bruchpilot at Drosophila neuromuscular junctions. Consistent with a block in axonal transport, we find a decrease in number of active zones and reduced neurotransmission in flies overexpressing Par-1 kinase. Interestingly, we find that Par-1 acts independently of Tau-one of the most well studied substrates of Par-1, revealing a presynaptic function for Par-1 that is independent of Tau. Thus, our study strongly suggests that there are distinct mechanisms that transport components of active zones and that they are tightly regulated.

  12. Removal of focal segmental glomerulosclerosis (FSGS) factor suPAR using CytoSorb.

    Science.gov (United States)

    Schenk, Heiko; Müller-Deile, Janina; Schmitt, Roland; Bräsen, Jan Hinrich; Haller, Hermann; Schiffer, Mario

    2017-12-01

    Treatment of primary focal segmental glomerulosclerosis (FSGS) and its recurrence after kidney transplantation associated with rapid deterioration of kidney function remains to be challenging despite advances in immunosuppressive therapy. The presence of circulating factors has been postulated to be a pivotal player in the pathogenesis of FSGS, although suPAR and CLCF-1 have been identified as the most promising causative factors. The potential therapeutic effect of suPAR elimination in an FSGS patient using CytoSorb, a hemoadsorption device that gained attention in the cytokine elimination in septic patients, was studied. Efficiency of total plasma exchange to remove suPAR was determined. CytoSorb hemoadsorption caused a 27.33% reduction of the suPAR level in a single treatment, whereas total plasma exchange showed a suPAR level reduction of 25.12% (n = 3; 95% confidence interval, 0.2777-0.8090; P < 0.01), which may indicate therapeutic potential in the treatment of primary FSGS and its recurrence in a kidney transplant. © 2017 Wiley Periodicals, Inc.

  13. Nanomechanical recognition of prognostic biomarker suPAR with DVD-ROM optical technology

    International Nuclear Information System (INIS)

    Bache, Michael; Bosco, Filippo G; Brøgger, Anna L; Frøhling, Kasper B; Boisen, Anja; Alstrøm, Tommy Sonne; Hwu, En-Te; Chen, Ching-Hsiu; Hwang, Ing-Shouh; Eugen-Olsen, Jesper

    2013-01-01

    In this work the use of a high-throughput nanomechanical detection system based on a DVD-ROM optical drive and cantilever sensors is presented for the detection of urokinase plasminogen activator receptor inflammatory biomarker (uPAR). Several large scale studies have linked elevated levels of soluble uPAR (suPAR) to infectious diseases, such as HIV, and certain types of cancer. Using hundreds of cantilevers and a DVD-based platform, cantilever deflection response from antibody–antigen recognition is investigated as a function of suPAR concentration. The goal is to provide a cheap and portable detection platform which can carry valuable prognostic information. In order to optimize the cantilever response the antibody immobilization and unspecific binding are initially characterized using quartz crystal microbalance technology. Also, the choice of antibody is explored in order to generate the largest surface stress on the cantilevers, thus increasing the signal. Using optimized experimental conditions the lowest detectable suPAR concentration is currently around 5 nM. The results reveal promising research strategies for the implementation of specific biochemical assays in a portable and high-throughput microsensor-based detection platform. (paper)

  14. PAR-1 mediated apoptosis of breast cancer cells by V. cholerae hemagglutinin protease.

    Science.gov (United States)

    Ray, Tanusree; Pal, Amit

    2016-05-01

    Bacterial toxins have emerged as promising agents in cancer treatment strategy. Hemagglutinin (HAP) protease secreted by Vibrio cholerae induced apoptosis in breast cancer cells and regresses tumor growth in mice model. The success of novel cancer therapies depends on their selectivity for cancer cells with limited toxicity for normal tissues. Increased expression of Protease Activated Receptor-1 (PAR-1) has been reported in different malignant cells. In this study we report that HAP induced activation and over expression of PAR-1 in breast cancer cells (EAC). Immunoprecipitation studies have shown that HAP specifically binds with PAR-1. HAP mediated activation of PAR-1 caused nuclear translocation of p50-p65 and the phosphorylation of p38 which triggered the activation of NFκB and MAP kinase signaling pathways. These signaling pathways enhanced the cellular ROS level in malignant cells that induced the intrinsic pathway of cell apoptosis. PAR-1 mediated apoptosis by HAP of malignant breast cells without effecting normal healthy cells in the same environment makes it a good therapeutic agent for treatment of cancer.

  15. "It was like reading a detective novel": Using PAR to work together for culture change.

    Science.gov (United States)

    Fortune, Darla; McKeown, Janet; Dupuis, Sherry; de Witt, Lorna

    2015-08-01

    Participatory action research (PAR), with its focus on engagement and collaboration, is uniquely suited to enhancing culture change initiatives in dementia care. Yet, there is limited literature of its application to culture change approaches in care settings, and even less in dementia specific care contexts. To address these gaps in the literature, the purpose of this paper is to examine the complexities of a PAR project aimed at changing the culture of dementia care in two diverse dementia care settings, including a long term care (LTC) and community care setting. Drawing from data gathered throughout the PAR process, we unpack the challenges experienced by participants working together to guide culture change within their respective care settings. These challenges include: overextending selves through culture change participation; fluctuating group membership; feeling uncertainty, confusion and apprehension about the process; frustratingly slow process; and seeking diverse group representation in decision making. We also highlight the potential for appreciative inquiry (AI) to be integrated with PAR to guide a process whereby participants involved in culture change initiatives can develop strategies to mitigate challenges they experience. We view the challenges and strategies shared here as being constructive to would-be culture change agents and hope this paper will move others to consider the use of PAR when engaging in culture change initiatives. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Lambeaux autofermants pour le traitement des brulures electriques du scalp par haut voltage

    Science.gov (United States)

    Hafidi, J.; El Mazouz, S.; El Mejatti, H.; Fejjal, N.; Gharib, N.E.; Abbassi, A.; Belmahi, A.M.

    2011-01-01

    Summary Les brûlures électriques par haut voltage sont responsables de gros dégâts tissulaires en immédiat et dans les jours suivant l’accident du fait de la chaleur importante dégagée par effet joule et de la thrombose microvasculaire évolutive. Les pertes de substances du scalp secondaires à ces brûlures nécessitent une couverture par lambeaux vu la destruction du périoste et du calvarium en regard. De juin 1997 à juin 2008, 15 patients ont été traités pour des pertes de substance du scalp secondaires à des brûlures électriques par haut voltage de diamètre allant de 8 à 11 cm et siégeant dans la région tonsurale. Ces patients ont été opérés dans la première semaine suivant l’accident. Les pertes de substance du scalp de taille moyenne secondaires à ces brûlures peuvent être couvertes per primam de façon fiable par des lambeaux locaux axialisés et multiples. Nous relatons l’expérience du Service de Chirurgie Plastique du Centre Hospitalier Universitaire Ibn-Sina, Rabat, Maroc, dans la gestion et la prise en charge de ces brûlures. PMID:22262963

  17. mTORC2 activation is regulated by the urokinase receptor (uPAR) in bladder cancer.

    Science.gov (United States)

    Hau, Andrew M; Leivo, Mariah Z; Gilder, Andrew S; Hu, Jing-Jing; Gonias, Steven L; Hansel, Donna E

    2017-01-01

    Mammalian target of rapamycin complex 2 (mTORC2) has been identified as a major regulator of bladder cancer cell migration and invasion. Upstream pathways that mediate mTORC2 activation remain poorly defined. Urokinase-type plasminogen activator receptor (uPAR) is a GPI-anchored membrane protein and known activator of cell-signaling. We identified increased uPAR expression in 94% of invasive human bladder cancers and in 54-71% of non-invasive bladder cancers, depending on grade. Normal urothelium was uPAR-immunonegative. Analysis of publicly available datasets identified uPAR gene amplification or mRNA upregulation in a subset of bladder cancer patients with reduced overall survival. Using biochemical approaches, we showed that uPAR activates mTORC2 in bladder cancer cells. Highly invasive bladder cancer cell lines, including T24, J82 and UM-UC-3 cells, showed increased uPAR mRNA expression and protein levels compared with the less aggressive cell lines, UROtsa and RT4. uPAR gene-silencing significantly reduced phosphorylation of Serine-473 in Akt, an mTORC2 target. uPAR gene-silencing also reduced bladder cancer cell migration and Matrigel invasion. S473 phosphorylation was observed by immunohistochemistry in human bladder cancers only when the tumors expressed high levels of uPAR. S473 phosphorylation was not controlled by uPAR in bladder cancer cell lines that are PTEN-negative; however, this result probably did not reflect altered mTORC2 regulation. Instead, PTEN deficiency de-repressed alternative kinases that phosphorylate S473. Our results suggest that uPAR and mTORC2 are components of a single cell-signaling pathway. Targeting uPAR or mTORC2 may be beneficial in patients with bladder cancer. Copyright © 2016. Published by Elsevier Inc.

  18. Fluorescent halite from Bochnia salt mine, Poland

    Science.gov (United States)

    Waluś, Edyta; Głąbińska, Dobrochna; Puławska, Aleksandra; Flasza, Michał; Manecki, Maciej

    2016-04-01

    The photoluminescence of selected halite crystals from Bochnia Salt Mine (Bochnia, Poland) were discovered in 2014. This is a result of contemporary precipitation from percolating waters. In most cases the fluorescence is observed in whole crystals or in zones of crystals. Only clear parts of transparent crystals are orange-red fluorescent in short UV light (320 nm). Chemical microanalysis by scanning electron microscopy/energy dispersive spectroscopy SEM/EDS indicates that this is activated by Mn and Pb. The concentration of Mn is similar in fluorescent and inactive salt and equals to 0.13 - 0.27 wt.%. The concentration of Pb, however, averages to 3.8 wt.% in fluorescent parts reaching only 1.9 wt.% elsewhere. There is no difference in the unit cell parameters determined by powder X-ray diffraction. The percolating waters contain some Mn (ca. 3.9 ppm) but the concentration of Pb is below the detection limits. The experiments of precipitation of halite from the solutions containing various concentrations of Mn and Pb were performed to simulate this fenomenon using solutions containing: 1 mg Pb/L and 80 mg Mn/L; 1 mg Pb/L and 0.8 mg Mn/L; 1 mg Pb/L and 0.6 mg Mn/L; and 0 mg Pb/L and 80 mg Mn/L. The results indicate that fluorescence is apparent when halite forms from solutions containing more than 0.8 mg Mn/L and more than 1 mg Pb/L. The presence of lead as co-activator is necessary requirement: Mn alone does not activate the fluorescence of halite. This is in accordance with the results of previous work (Murata et al., 1946; Sidike et al., 2002). Rock salt in the mine does not show fluorescence at all. Fluorescence of contemporary salt in Bochnia salt mine is a result of mining activity and slight, sporadic contamination with traces of Mn and Pb. This work is partially funded by AGH research grant no 11.11.140.319. Murata K. J., Smith R. L., 1946. Manganese and lead as coactivators of red fluorescence in halite, American Mineralogist, Volume 31, pages 527

  19. Abnormal chloride homeostasis in the substancia nigra pars reticulata contributes to locomotor deficiency in a model of acute liver injury.

    Directory of Open Access Journals (Sweden)

    Yan-Ling Yang

    Full Text Available BACKGROUND: Altered chloride homeostasis has been thought to be a risk factor for several brain disorders, while less attention has been paid to its role in liver disease. We aimed to analyze the involvement and possible mechanisms of altered chloride homeostasis of GABAergic neurons within the substantia nigra pars reticulata (SNr in the motor deficit observed in a model of encephalopathy caused by acute liver failure, by using glutamic acid decarboxylase 67 - green fluorescent protein knock-in transgenic mice. METHODS: Alterations in intracellular chloride concentration in GABAergic neurons within the SNr and changes in the expression of two dominant chloride homeostasis-regulating genes, KCC2 and NKCC1, were evaluated in mice with hypolocomotion due to hepatic encephalopathy (HE. The effects of pharmacological blockade and/or activation of KCC2 and NKCC1 functions with their specific inhibitors and/or activators on the motor activity were assessed. RESULTS: In our mouse model of acute liver injury, chloride imaging indicated an increase in local intracellular chloride concentration in SNr GABAergic neurons. In addition, the mRNA and protein levels of KCC2 were reduced, particularly on neuronal cell membranes; in contrast, NKCC1 expression remained unaffected. Furthermore, blockage of KCC2 reduced motor activity in the normal mice and led to a further deteriorated hypolocomotion in HE mice. Blockade of NKCC1 was not able to normalize motor activity in mice with liver failure. CONCLUSION: Our data suggest that altered chloride homeostasis is likely involved in the pathophysiology of hypolocomotion following HE. Drugs aimed at restoring normal chloride homeostasis would be a potential treatment for hepatic failure.

  20. New Approaches in Soil Organic Matter Fluorescence; A Solid Phase Fluorescence Approach

    Science.gov (United States)

    Bowman, M. M.; Sanclements, M.; McKnight, D. M.

    2017-12-01

    Fluorescence spectroscopy is a well-established technique to investigate the composition of organic matter in aquatic systems and is increasingly applied to soil organic matter (SOM). Current methods require that SOM be extracted into a liquid prior to analysis by fluorescence spectroscopy. Soil extractions introduce an additional layer of complexity as the composition of the organic matter dissolved into solution varies based upon the selected extractant. Water is one of the most commonly used extractant, but only extracts the water-soluble fraction of the SOM with the insoluble soil organic matter fluorescence remaining in the soil matrix. We propose the use of solid phase fluorescence on whole soils as a potential tool to look at the composition of organic matter without the extraction bias and gain a more complete understand of the potential for fluorescence as a tool in terrestrial studies. To date, the limited applications of solid phase fluorescence have ranged from food and agriculture to pharmaceutical with no clearly defined methods and limitations available. We are aware of no other studies that use solid phase fluorescence and thus no clear methods to look at SOM across a diverse set of soil types and ecosystems. With this new approach to fluorescence spectroscopy there are new challenges, such as blank correction, inner filter effect corrections, and sample preparation. This work outlines a novel method for analyzing soil organic matter using solid phase fluorescence across a wide range of soils collected from the National Ecological Observatory Network (NEON) eco-domains. This method has shown that organic matter content in soils must be diluted to 2% to reduce backscattering and oversaturation of the detector in forested soils. In mineral horizons (A) there is observed quenching of the humic-like organic matter, which is likely a result of organo-mineral complexation. Finally, we present preliminary comparisons between solid and liquid phase