577 research outputs found
Water-Exchange Study Revealed Unexpected Substitution Behavior of [(CO)2(NO)Re(H2O)3]2+ in Aqueous Media
No full textCopyright © 2006 American Chemical SocietyMarie-Line Lehaire, Pascal V. Grundler, Stefan Steinhauser, Niklaus Marti, Lothar Helm, Kaspar Hegetschweiler, Roger Schibli, and André E. Merbac
Mechanistic changeover for the water substitution on fac-[(CO)(3)Re(H(2)O)(3)](+) revealed by high-pressure NMR
No full textCopyright © 2004 American Chemical SocietyPascal V. Grundler, Bernadette Salignac, Sonia Cayemittes, Roger Alberto, and André E. Merbac
Cross section measurement of terbium radioisotopes for an optimized 155Tb production with an 18 MeV medical PET cyclotron.
No full text155Tb [t1/2 = 5.32 d, Eγ = 87 keV (32%); 105 keV (25%) (IAEA, 2021)] is a novel promising radionuclide for theranostic applications in nuclear medicine. Its physical properties make it suitable for single photon emission computed tomography (SPECT) imaging, while its chemistry allows it to be used as a diagnostic partner for therapeutic radiolanthanides or pseudo-radiolanthanides, such as 177Lu and 90Y. Moreover, 155Tb could be used as a precise diagnostic match for the β--emitter 161Tb, opening doors for the true theranostics concept. The availability of 155Tb in quantity and quality suitable for medical applications is an open issue and its production with medical cyclotrons via the 155Gd(p,n)155Tb and 156Gd(p,2n)155Tb nuclear reactions represents a possible but challenging solution. For this purpose, an accurate knowledge of the production cross sections is mandatory. In this paper, we report on the measurement of the production cross sections of 155Tb and other terbium radionuclides formed by proton irradiation of natGd2O3, 155Gd2O3 and 156Gd2O3 enriched targets, performed at the Bern University Hospital cyclotron laboratory. On the basis of the obtained results, the production yield and purity were calculated to assess the optimal irradiation conditions. The results of several production tests are also presented
Cross-section measurement of thulium radioisotopes with an 18 MeV medical PET cyclotron for an optimized 165Er production.
No full text165Er is a pure Auger-electron emitter with promising characteristics for therapeutic applications in nuclear medicine. The short penetration path and high Linear Energy Transfer (LET) of the emitted Auger electrons make 165Er particularly suitable for treating small tumor metastases. Several production methods based on the irradiation with charged particles of Er and Ho targets can be found in the literature. In this paper, we report on the study of 165Er indirect production performed via the 166Er(p,2n)165Tm →165Er reaction at the 18 MeV Bern medical cyclotron. Despite the use of highly enriched 166Er2O3 targets, several Tm radioisotopes are produced during the irradiation, making the knowledge of the cross sections involved crucial. For this reason, a precise investigation of the cross sections of the relevant nuclear reactions in the energy range of interest was performed by irradiating Er2O3 targets with different isotopic enrichment levels and using a method based on the inversion of a linear system of equations. For the reactions 164Er(p, γ)165Tm, 166Er(p,n)166Tm, 166Er(p, γ)167Tm, 167Er(p,3n)165Tm, 167Er(p, γ)168Tm, 168Er(p,2n)167Tm and 170Er(p,3n)168Tm, the nuclear cross section was measured for the first time. From the results obtained, the production yield and purity of the parent radioisotope 165Tm were calculated to assess the optimal irradiation conditions. Several production tests with solid targets were performed to confirm these findings
Samuel Beckett and the Writers of Port-Royal
No full textIt has been observed that ‘the literary influences on Beckett have been far more important than has been acknowledged, and more important indeed, than the philosophical influences’ (Smith 2002: 3). The truth of this statement is evidenced by the description that scholars have given of Samuel Beckett’s relationship to seventeenth century French classicism. To date, critical interest has been limited for the most part to the figure of the philosopher René Descartes on the (fragile) grounds that Beckett was exclusively concerned with the Cartesian imperative of clarity and order, the fundamental dualism between body and mind, and Nominalism.
Together with the assumption that Beckett’s vision was essentially Cartesian, his literary filiation with Pascal was suggested by critics, but only in terms of Beckett’s formal approach to the theatre. In his short article on En attendant Godot in 1953, the playwright Jean Anouilh was among the first reviewers to suggest that Beckett’s drama synthesizes the encounter between ‘classicism’ and a ‘modern’ form of art. It is well known that Beckett retained a lifelong admiration for Pascal – indeed, Pascal was one of his ‘old chestnuts’ (Knowlson 1997: 653). Little attention has been paid, however, to the originality of Pascal’s thought, the specific nature of his prose, and the impact these might have had upon Beckett’s mature work, especially the trilogy and the subsequent short prose. Yet, in the literary and philosophical context of post-war France, Beckett’s filiation with Pascal, their corresponding preoccupations, were evident to his contemporaries, who identified Pascal as an underlying presence in his works
XAS evidence for the stability of polytellurides in hydrothermal fluids up to 599 degree(s) C, 800 bar
No full textAlthough the crustal abundance of tellurium (Te) is about half of that of gold (Au), several classes of Au deposits are highly enriched in Te. Our understanding of the nature of this Au-Te association is hampered by the lack of experimental studies of Te geochemistry at elevated temperature. We characterized the structure of polytelluride solutions from room temperature to 599ºC at 800 bar using in situ X-ray absorption spectroscopy. Both ab-initio XANES and EXAFS fits show that polytellurides are stable up to the highest temperature with planar structures (four-or threefold coordination of Te) giving way to linear chaines (e.g. Te2-ion) at temperatures above --200ºC. This is the first experimental confirmation of the thermal stability of polytelluride species. The data shows that polytellurides play an important role in Te transport in reduced S-rich or CO2-rich solutions and vapors.Joël Brugger, Barbara E. Etschmann, Pascal V. Grundler, Weihua Liu, Denis Testemale and Allan Pringhttp://www.minsocam.org/msa/ammin/toc/2012/AS12.htm
At certe videre videor. Cartesio alla prova di Pascal
No full textThe author proposes a comparison between Descartes and Pascal starting from the common pathic background in which the theory is generated for both. And yet, despite the common basis, Pascal's difference emerges even more acutely and goes in the direction of a radical exposition of the subject
A novel pre-treatment of calaverite by hydrothermal mineral replacement reactions
No full textWe report a new method for pre-treatment of refractory gold-bearing tellurides employing the hydrothermal mineral replacement reactions. The method is illustrated by the replacement of calaverite by metallic gold at 150-250 °C under vapor saturated pressures. The influences of temperature, pH, and additional salts (NaCl and Na2SO4) on the conversion rate were investigated using the orthogonal array design method. The results indicate that temperature is the most significant factor, followed by pH, and then additional salts. The optimal condition for fast and low cost conversion is 200 °C, pH 6.0, 0.01 M NaCl, and <38 μm particle size. Under this condition, the conversion can be completed within 15 h. These preliminary results indicate that the hydrothermal mineral replacement reaction is a promising pre-treating step for gold-bearing tellurides processing. © 2009 Elsevier Ltd. All rights reserved.Jing Zhao, Fang Xia, Allan Pring, Joël Brugger, Pascal V. Grundler and Guorong Che
Prefazione a Pascal e la filosofia
No full textThe author presents the distinctive features of the work "Pascal e la filosofia"
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
No full textThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
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