| 1. |
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| 2. |
- Rodriguez, D., et al.
(författare)
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MATS and LaSpec : High-precision experiments using ion traps and lasers at FAIR
- 2010
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Ingår i: The European physical journal. Special topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 183, s. 1-123
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Forskningsöversikt (refereegranskat)abstract
- Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique ""fingerprint"". Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10(-5) to below 10(-8) for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10(-9) can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e. g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with beta-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
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| 3. |
- Flanagan, K. T., et al.
(författare)
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Nuclear Spins and Magnetic Moments of Cu-71,Cu-73,Cu-75 : Inversion of pi 2p(3/2) and pi 1f(5/2) Levels in Cu-75
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:14, s. 142501-
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Tidskriftsartikel (refereegranskat)abstract
- We report the first confirmation of the predicted inversion between the pi 2p(3/2) and pi 1f(5/2) nuclear states in the nu g(9/2) midshell. This was achieved at the ISOLDE facility, by using a combination of in-source laser spectroscopy and collinear laser spectroscopy on the ground states of Cu-71,Cu-73,Cu-75, which measured the nuclear spin and magnetic moments. The obtained values are mu(Cu-71)=+2.2747(8)mu(N), mu(Cu-73)=+1.7426(8)mu(N), and mu(Cu-75)=+1.0062(13)mu(N) corresponding to spins I=3/2 for Cu-71,Cu-73 and I=5/2 for Cu-75. The results are in fair agreement with large-scale shell-model calculations.
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| 4. |
- Hartman, Henrik, et al.
(författare)
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Negative ion relaxation and reactions in a cryogenic storage ring
- 2020
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Ingår i: Journal of Physics: Conference Series Vol 1412. - : IOP Publishing. - 1742-6588 .- 1742-6596.
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Konferensbidrag (refereegranskat)abstract
- An overview of recent experimental results of studies of negative atomic and molecular ions in the Double ElectroStatic Ion-Ring ExpEriment, DESIREE is given. Metastable level lifetimes in atomic negative ions have been measured by time-dependent laser photodetachment. Rotational relaxation of diatomic anions is studied by near-threshold photodetachment. Spontaneous decays of small metal cluster anions by electron emission and fragmentation is studied with decay-channel specificity. Finally, mutual neutralisation of pairs of negative and positive ions has been investigated with initial and final state selectivity.
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| 5. |
- Rodriguez, Sébastien, et al.
(författare)
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Science goals and new mission concepts for future exploration of Titan's atmosphere, geology and habitability : titan POlar scout/orbitEr and in situ lake lander and DrONe explorer (POSEIDON)
- 2022
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 54:2-3, s. 911-973
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Tidskriftsartikel (refereegranskat)abstract
- In response to ESA’s “Voyage 2050” announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn’s largest moon Titan. Titan, a “world with two oceans”, is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System with habitability potential. Titan’s remarkable nature was only partly revealed by the Cassini-Huygens mission and still holds mysteries requiring a complete exploration using a variety of vehicles and instruments. The proposed mission concept POSEIDON (Titan POlar Scout/orbitEr and In situ lake lander DrONe explorer) would perform joint orbital and in situ investigations of Titan. It is designed to build on and exceed the scope and scientific/technological accomplishments of Cassini-Huygens, exploring Titan in ways that were not previously possible, in particular through full close-up and in situ coverage over long periods of time. In the proposed mission architecture, POSEIDON consists of two major elements: a spacecraft with a large set of instruments that would orbit Titan, preferably in a low-eccentricity polar orbit, and a suite of in situ investigation components, i.e. a lake lander, a “heavy” drone (possibly amphibious) and/or a fleet of mini-drones, dedicated to the exploration of the polar regions. The ideal arrival time at Titan would be slightly before the next northern Spring equinox (2039), as equinoxes are the most active periods to monitor still largely unknown atmospheric and surface seasonal changes. The exploration of Titan’s northern latitudes with an orbiter and in situ element(s) would be highly complementary in terms of timing (with possible mission timing overlap), locations, and science goals with the upcoming NASA New Frontiers Dragonfly mission that will provide in situ exploration of Titan’s equatorial regions, in the mid-2030s.
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| 6. |
- Vigren, E., et al.
(författare)
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Collision-induced dissociation of ∼2-MeV O+3 and N+3 ions
- 2013
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 87:5
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Tidskriftsartikel (refereegranskat)abstract
- We present a study into the collision-induced dissociation (possibly including electron stripping) of O-3(+) and N-3(+) with rest gas molecules (predominantly H-2) in the heavy-ion storage ring CRYRING. The projectile ions had kinetic energies of 1.96 MeV (O-3(+)) and 2.25 MeV (N-3(+)) and from the experimental data we could derive the relative importance of the channels that produce at least one neutral product fragment. The dominant type of fragmentation for both ions involves the production of a single neutral fragment, namely an individual atom. We also find pronounced dissimilarities when comparing the O-3(+) and N-3(+) results, which we link to the stronger chemical bonds in the nitrogen system.
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| 7. |
- Wakelam, V., et al.
(författare)
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A KINETIC DATABASE FOR ASTROCHEMISTRY (KIDA)
- 2012
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 199:1, s. 21-
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Tidskriftsartikel (refereegranskat)abstract
- We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database for Astrochemistry (KIDA), this database consists of gas-phase reactions with rate coefficients and uncertainties that will be vetted to the greatest extent possible. Submissions of measured and calculated rate coefficients are welcome, and will be studied by experts before inclusion into the database. Besides providing kinetic information for the interstellar medium, KIDA is planned to contain such data for planetary atmospheres and for circumstellar envelopes. Each year, a subset of the reactions in the database (kida.uva) will be provided as a network for the simulation of the chemistry of dense interstellar clouds with temperatures between 10 K and 300 K. We also provide a code, named Nahoon, to study the time-dependent gas-phase chemistry of zero-dimensional and one-dimensional interstellar sources.
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| 8. |
- Ehlerding, A., et al.
(författare)
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The dissociative recombination of fluorocarbon ions III : CF2+ and CF3
- 2006
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 39:4, s. 805-812
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Tidskriftsartikel (refereegranskat)abstract
- Cross sections and branching ratios are presented for the dissociative recombination of the CF2+ and C-3(+) ions with electrons. It is found that the channel producing CF + F is dominant for the reaction with CF2+ and the production of CF2 + F is dominant for the reaction with CF3+. The cross sections for these two ions are very similar.
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| 9. |
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| 10. |
- Geppert, W. D., et al.
(författare)
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Dissociative recombination of CD3OD2
- 2005
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Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 1, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of the different reaction pathways and the overall rate of the dissociative recombination of CD3OD2 + were measured at the CRYRING storage ring located at the Manne Siegbahn Laboratory in Stockholm, Sweden. A preliminary analysis of the data yielded that formation of methanol accounts for only 6±2% of the total reaction rate. Largely, dissociative recombination of CD3OD 2 + involves fragmentation of the C-O bond, the major process being the three-body break-up forming CD3, OD and D (branching ratio 0.59). A non-negligible formation of interstellar methanol by the previously proposed mechanism is therefore very unlikely.
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| 11. |
- Geppert, W.D., et al.
(författare)
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Dissociative recombination of protonated methanol
- 2006
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Ingår i: Faraday discussions. - Cambridge : Royal Society of Chemistry (RSC). - 1359-6640 .- 1364-5498. ; 133, s. 177-190
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of the different reaction pathways and the overall rate coefficients of the dissociative recombination reactions of CH3OH2+ and CD3OD2+ have been measured at the CRYRING storage ring located in Stockholm, Sweden. Analysis of the data yielded the result that formation of methanol or deuterated methanol accounted for only 3 and 6% of the total rate in CH3OH2+ and CD3OD2+, respectively. Dissociative recombination of both isotopomeres mainly involves fragmentation of the C - O bond, the major process being the three-body break-up forming CH3, OH and H (CD3, OD and D). The overall cross sections are best fitted by sigma = 1.2 +/- 0.1 x 10(-15) E-1.15 +/- 0.02 cm(2) and sigma = 9.6 +/- 0.9 x 10(-16) E-1.20 +/- 0.02 cm(2) for CH3OH2+ and CD3OD2+, respectively. From these values thermal reaction rate coefficients of k(T) = 8.9 +/- 0.9 x 10(-7) (T/300) (- 0.59 +/- 0.02) cm(3) s(-1) (CH3OH2+) and k( T) = 9.1 +/- 0.9 x 10(-7) (T/ 300) (- 0.63 +/- 0.02) cm(3) s(-1)(CD3OD2+) can be calculated. A non-negligible formation of interstellar methanol by the previously proposed mechanism via radiative association of CH3+ and H2O and subsequent dissociative recombination of the resulting CH3OH2+ ion to yield methanol and hydrogen atoms is therefore very unlikely.
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| 12. |
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| 13. |
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| 14. |
- Zhaunerchyk, V., et al.
(författare)
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Dissociative recombination study of N-3(+) : Cross section and branching fraction measurements
- 2007
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 127:1, s. 014305-
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Tidskriftsartikel (refereegranskat)abstract
- We report an investigation into the dissociative recombination of the azide radical cation, N-3(+). The reaction rate constant has been measured to be 6.47x10(-7) cm(3) s(-1) at room temperature. This value is smaller than those reported earlier for the ion-electron neutralization of N-3(+) at nitrogen atmospheric pressure. A strong propensity to dissociate through the N-2+N channel has been observed.
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| 15. |
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| 16. |
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| 17. |
- Al-Khalili, A, et al.
(författare)
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Dissociative recombination cross section and branching ratios of protonated dimethyl disulfide and N-methylacetamide
- 2004
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:12, s. 5700-5708
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Tidskriftsartikel (refereegranskat)abstract
- Dimethyl disulfide (DMDS) and N-methylacetamide are two first choice model systems that represent the disulfide bridge bonding and the peptide bonding in proteins. These molecules are therefore suitable for investigation of the mechanisms involved when proteins fragment under electron capture dissociation (ECD). The dissociative recombination cross sections for both protonated DMDS and protonated N-methylacetamide were determined at electron energies ranging from 0.001 to 0.3 eV. Also, the branching ratios at 0 eV center-of-mass collision energy were determined. The present results give support for the indirect mechanism of ECD, where free hydrogen atoms produced in the initial fragmentation step induce further decomposition. We suggest that both indirect and direct dissociations play a role in ECD.
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| 18. |
- Geppert, W D, et al.
(författare)
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Dissociative recombination of nitrile ions : DCCCN+ and DCCCND
- 2004
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 613:2, s. 1302-1309
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of DCCCN+ and DCCCND+ using the CRYRING ion storage ring. In the case of DCCCN+ the dissociation yielding D + C3N and those leading to two fragments containing a pair of heavy atoms dominate, whereas pathways producing a fragment with three heavy atoms play only a minor role. Conversely, for DCCCND+, only those channels preserving the carbon chain or producing two fragments with a pair of heavy atoms each are detected. The cross sections of the reactions are very similar and can be fitted to the expressions sigma = (2.9 +/- 0.5) x 10(-15)E(eV)(-1.05 +/- 0.02) cm(2) and sigma = (2.3 +/- 0.4) x 10(-15)E(eV)(-1.10 +/- 0.02) cm(2) for DCCCN+ and DCCCND+, respectively. From these data, thermal reaction rates of k(T) = (1.5 +/- 0.3) x 10(-6)(T/300 K)(-0.60 +/- 0.02) cm(3) s(-1) and k(T) = (1.5 +/- 0.3) x 10(-6)(T/300 K)(-0.58 +/- 0.02) cm(3) s(-1) were calculated for DCCCN+ and DCCCND+, respectively. These rates and branching ratios are compared with those hitherto used in astrophysical models.
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| 19. |
- Geppert, W D, et al.
(författare)
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Dissociative recombination of (SO2+)-O-18 : Evidence for three-body breakup
- 2004
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 610:2, s. 1228-1233
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of (SO2+)-O-18 using the CRYRING ion storage ring. The branching ratio of the (SO2+)-O-18 + e(-)-->(SO)-O-18+O-18 channel amounts to 61%, while the three-body breakup (SO2+)-O-18 + e(-)-->S+2(18)O accounts for the remaining 39% of the total reaction. The cross section of the reaction could be fitted by the expression sigma=(1.2+/-0.4)x10(-15) E-0.96+/-0.02 cm(2), which leads to a thermal reaction rate of k(T)=(4.6+/-0.2)x10(-7)(T/300 K)(-0.52+/-0.02) cm(3) mol(-1) s(-1).
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| 20. |
- Geppert, W. D., et al.
(författare)
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Formation of biomolecule precursors in space
- 2007
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 88:1, s. 012068-
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Tidskriftsartikel (refereegranskat)abstract
- Alcohols and nitriles not only play an important role as templates for synthesis of larger molecules in the interstellar medium and planetary atmospheres, but they can also be regarded as precursors for biomolecules. Alcohols can form carbohydrates through reaction with HCO and nitriles can be hydrolysed to amino acids in aqueous solutions, which is the final step of the well-known Strecker synthesis. Therefore the question of the pathways of formation of alcohols and nitriles and the efficiency and the product distribution of their subsequent degradation reactions in the above-mentioned astrophysical environments is of great interest. In both processes dissociative recombination reactions of protonated nitriles and alcohols may play a major role and are included in models of interstellar clouds and planetary atmospheres. However, the reaction rate coefficients and product branching ratios for the majority of these processes are so far still unknown, which adversely affects the quality of predictions of model calculations. In this Contribution, we therefore present branching ratios and rate constants of the dissociative recombination of protonated methanol (CH3OH 2), as well as protonated acetonitrile (CH3CNH +), acrylonitrile (C2H3CNH+) and cyanoacetylene (HC3NH+). The impact of the obtained new data on model calculations of abundances of important interstellar molecules in dark clouds is discussed.
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| 21. |
- Hellberg, F, et al.
(författare)
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Investigating the breakup dynamics of dihydrogen sulfide ions recombining with electrons
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 122:22, s. 224314-
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents results concerning measurements of the dissociative recombination (DR) of dihydrogen sulfide ions. In combination with the ion storage ring CRYRING an imaging technique was used to investigate the breakup dynamics of the three-body channel in the DR of (SD2+)-S-32. The two energetically available product channels S(P-3)+2D(S-2) and S(D-1)+2D(S-2) were both populated, with a branching fraction of the ground-state channel of 0.6(0.1). Information about the angle between the two deuterium atoms upon dissociation was obtained together with information about how the available kinetic energy was distributed between the two light fragments. The recombination cross sections as functions of energy in the interval of 1 meV to 0.3 eV in the center-of-mass frame are presented for (SH2+)-S-34. The thermal rate coefficient for the DR of (SH2+)-S-34 was determined to be (4.8 +/- 1.0)x10(-7)(T/300)(-0.72 +/- 0.1) cm(3) s(-1) over this interval.
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| 22. |
- Losiak, A., et al.
(författare)
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Dating a small impact crater : An age of Kaali crater (Estonia) based on charcoal emplaced within proximal ejecta
- 2016
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Ingår i: Meteoritics and Planetary Science. - : Wiley. - 1086-9379 .- 1945-5100. ; 51:4, s. 681-695
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Tidskriftsartikel (refereegranskat)abstract
- The estimates of the age of the Kaali impact structure (Saaremaa Island, Estonia) provided by different authors vary by as much as 6000years, ranging from similar to 6400 to similar to 400 before current era (BCE). In this study, a new age is obtained based on C-14 dating charred plant material within the proximal ejecta blanket, which makes it directly related to the impact structure, and not susceptible to potential reservoir effects. Our results show that the Kaali crater was most probably formed shortly after 1530-1450 BCE (3237 +/- 10 C-14 yr BP). Saaremaa was already inhabited when the bolide hit the Earth, thus, the crater-forming event was probably witnessed by humans. There is, however, no evidence that this event caused significant change in the material culture (e.g., known archeological artifacts) or patterns of human habitation on Saaremaa.
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| 23. |
- Mlecnik, B, et al.
(författare)
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Clinical Performance of the Consensus Immunoscore in Colon Cancer in the Asian Population from the Multicenter International SITC Study
- 2022
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:18
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In this study, we evaluated the prognostic value of Immunoscore in patients with stage I–III colon cancer (CC) in the Asian population. These patients were originally included in an international study led by the Society for Immunotherapy of Cancer (SITC) on 2681 patients with AJCC/UICC-TNM stages I–III CC. METHODS: CD3+ and cytotoxic CD8+ T-lymphocyte densities were quantified in the tumor and invasive margin by digital pathology. The association of Immunoscore with prognosis was evaluated for time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS). RESULTS: Immunoscore stratified Asian patients (n = 423) into different risk categories and was not impacted by age. Recurrence-free rates at 3 years were 78.5%, 85.2%, and 98.3% for a Low, Intermediate, and High Immunoscore, respectively (HR[Low-vs-High] = 7.26 (95% CI 1.75−30.19); p = 0.0064). A High Immunoscore showed a significant association with prolonged TTR, OS, and DFS (p < 0.05). In Cox multivariable analysis stratified by center, Immunoscore association with TTR was independent (HR[Low-vs-Int+High] = 2.22 (95% CI 1.10–4.55) p = 0.0269) of the patient’s gender, T-stage, N-stage, sidedness, and MSI status. A significant association of a High Immunoscore with prolonged TTR was also found among MSS (HR[Low-vs-Int+High] = 4.58 (95% CI 2.27−9.23); p ≤ 0.0001), stage II (HR[Low-vs-Int+High] = 2.72 (95% CI 1.35−5.51); p = 0.0052), low-risk stage-II (HR[Low-vs-Int+High] = 2.62 (95% CI 1.21−5.68); p = 0.0146), and high-risk stage II patients (HR[Low-vs-Int+High] = 3.11 (95% CI 1.39−6.91); p = 0.0055). CONCLUSION: A High Immunoscore is significantly associated with the prolonged survival of CC patients within the Asian population.
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| 24. |
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| 25. |
- Mlecnik, B, et al.
(författare)
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Multicenter International Study of the Consensus Immunoscore for the Prediction of Relapse and Survival in Early-Stage Colon Cancer
- 2023
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: The prognostic value of Immunoscore was evaluated in Stage II/III colon cancer (CC) patients, but it remains unclear in Stage I/II, and in early-stage subgroups at risk. An international Society for Immunotherapy of Cancer (SITC) study evaluated the pre-defined consensus Immunoscore in tumors from 1885 AJCC/UICC-TNM Stage I/II CC patients from Canada/USA (Cohort 1) and Europe/Asia (Cohort 2). METHODS: Digital-pathology is used to quantify the densities of CD3+ and CD8+ T-lymphocyte in the center of tumor (CT) and the invasive margin (IM). The time to recurrence (TTR) was the primary endpoint. Secondary endpoints were disease-free survival (DFS), overall survival (OS), prognosis in Stage I, Stage II, Stage II-high-risk, and microsatellite-stable (MSS) patients. RESULTS: High-Immunoscore presented with the lowest risk of recurrence in both cohorts. In Stage I/II, recurrence-free rates at 5 years were 78.4% (95%-CI, 74.4–82.6), 88.1% (95%-CI, 85.7–90.4), 93.4% (95%-CI, 91.1–95.8) in low, intermediate and high Immunoscore, respectively (HR (Hi vs. Lo) = 0.27 (95%-CI, 0.18–0.41); p < 0.0001). In Cox multivariable analysis, the association of Immunoscore to outcome was independent (TTR: HR (Hi vs. Lo) = 0.29, (95%-CI, 0.17–0.50); p < 0.0001) of the patient’s gender, T-stage, sidedness, and microsatellite instability-status (MSI). A significant association of Immunoscore with survival was found for Stage II, high-risk Stage II, T4N0 and MSS patients. The Immunoscore also showed significant association with TTR in Stage-I (HR (Hi vs. Lo) = 0.07 (95%-CI, 0.01–0.61); P = 0.016). The Immunoscore had the strongest (69.5%) contribution χ2 for influencing survival. Patients with a high Immunoscore had prolonged TTR in T4N0 tumors even for patients not receiving chemotherapy, and the Immunoscore remained the only significant parameter in multivariable analysis. CONCLUSION: In early CC, low Immunoscore reliably identifies patients at risk of relapse for whom a more intensive surveillance program or adjuvant treatment should be considered.
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| 26. |
- Montaigne, Helen, et al.
(författare)
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Dissociative recombination of the thioformyl (HCS+) and carbonyl sulfide (OCS+) cations
- 2005
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 631:1, s. 653-659
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of HCS+ and OCS+ at the CRYRING ion storage ring. In the case of OCS+, the channel leading to CO + S ( 83%) dominates, whereas the other exoergic pathways leading to CS + O (14%) and C + SO (3%) are of lesser importance. In the case of HCS+, fracture of the C - S bond is predominant (81%), with the production of H + CS accounting for the remainder (19%). The cross section of the reaction could be fitted by the expressions sigma = 1.41 x 10(-15)E(eV)(-1.11) and 4.47 x 10(-16)E(eV) (-1.14) cm(2) for HCS+ and OCS+, respectively. The derived energy dependences of the thermal reaction rate coefficients can be fitted by k(T) 9.7 x 10(-7)(T/300)(-0.57) and 3.5 x 10(-7)(T/300)(-0.62) cm(3) s(-1) for HCS+ and OCS+, respectively. We use these data to perform model calculations on the HCS+/CS abundance ratio in dark clouds and find that the models using the UMIST and Ohio State University databases have even more difficulty in accounting for the large observed ratio.
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| 27. |
- Novotný, O., et al.
(författare)
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DISSOCIATIVE RECOMBINATION MEASUREMENTS OF NH+ USING AN ION STORAGE RING
- 2014
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 792:2
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated dissociative recombination (DR) of NH+ with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present our measured absolute merged-beams recombination rate coefficient for collision energies from 0 to 12 eV. From these data, we have extracted a cross section, which we have transformed to a plasma rate coefficient for the collisional plasma temperature range from T-p1 = 10 to 18,000 K. We show that the NH+ DR rate coefficient data in current astrochemical models are underestimated by up to a factor of approximately nine. Our new data will result in predicted NH+ abundances lower than those calculated by present models. This is in agreement with the sensitivity limits of all observations attempting to detect NH+ in interstellar clouds.
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| 28. |
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| 29. |
- Novotny, O, et al.
(författare)
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The dissociative recombination of fluorocarbon ions : II. CF
- 2005
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 38:10, s. 1471-1482
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Tidskriftsartikel (refereegranskat)abstract
- The dissociative recombination and excitation of CF+ have been measured at the ASTRID and CRYRING storage rings. Though examination of the available potential energy curves would suggest that the recombination rate would be large for this ion, in fact a rate constant of 5.2 +/- 1.0 x 10(-8) (T-e/300)(-0.8) cm(3) s(-1) was found. The recombination cross section at low energies falls off to a minimum at 0.5 eV centre-of-mass collision energy but exhibits resonances at energies above this. The dissociative excitation cross section leading to C+ + F was also measured and this displays an onset beginning at about 7 eV.
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| 30. |
- Thomas, R. D., et al.
(författare)
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Hot Water from Cold. The Dissociative Recombination of Water Cluster Ions
- 2010
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 114:14, s. 4843-4846
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Tidskriftsartikel (refereegranskat)abstract
- Dissociative recombination of the Zundel cation D(5)O(2)(+) almost exclusively produces D + 2 D(2)O with a maximum kinetic energy release of 5.1 eV. An imaging technique is used to investigate the distribution of the available reaction energy among these products. Analysis shows that as much as 4 eV can be stored internally by the molecular fragments, with a preference for producing highly excited molecular fragments, and that the deuteron shows a nonrandom distribution of kinetic energies. A possible mechanism and the implications for these observations are addressed.
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| 31. |
- Wakelam, V., et al.
(författare)
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Reaction Networks for Interstellar Chemical Modelling : Improvements and Challenges
- 2010
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 156:04-jan, s. 13-72
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Forskningsöversikt (refereegranskat)abstract
- We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes-ion-neutral reactions, neutral-neutral reactions, radiative association, and dissociative recombination-is reviewed. Emphasis is placed on those key reactions that have been identified, by sensitivity analyses, as 'crucial' in determining the predicted abundances of the species observed in the interstellar medium. These sensitivity analyses have been carried out for gas-phase models of three representative, molecule-rich, astronomical sources: the cold dense molecular clouds TMC-1 and L134N, and the expanding circumstellar envelope IRC +10216. Our review has led to the proposal of new values and uncertainties for the rate coefficients of many of the key reactions. The impact of these new data on the predicted abundances in TMC-1 and L134N is reported. Interstellar dust particles also influence the observed abundances of molecules in the interstellar medium. Their role is included in gas-grain, as distinct from gas-phase only, models. We review the methods for incorporating both accretion onto, and reactions on, the surfaces of grains in such models, as well as describing some recent experimental efforts to simulate and examine relevant processes in the laboratory. These efforts include experiments on the surface-catalyzed recombination of hydrogen atoms, on chemical processing on and in the ices that are known to exist on the surface of interstellar grains, and on desorption processes, which may enable species formed on grains to return to the gas-phase.
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| 32. |
- Wakelam, V., et al.
(författare)
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The 2014 KIDA Network for Interstellar Chemistry
- 2015
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 217:2
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Tidskriftsartikel (refereegranskat)abstract
- Chemical models used to study the chemical composition of the gas and the ices in the interstellar medium are based on a network of chemical reactions and associated rate coefficients. These reactions and rate coefficients are partially compiled from data in the literature, when available. We present in this paper kida.uva.2014, a new updated version of the kida.uva public gas-phase network first released in 2012. In addition to a description of the many specific updates, we illustrate changes in the predicted abundances of molecules for cold dense cloud conditions as compared with the results of the previous version of our network, kida.uva.2011.
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| 33. |
- Yang, B., et al.
(författare)
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Exploring high-energy doubly excited states of NH by dissociative recombination of NH
- 2014
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 47:3, s. 035201-
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated electron capture by NH+ resulting in dissociative recombination (DR). The impact energies studied of similar to 4-12 eV extend over the range below the two lowest predicted NH+ dissociative states in the Franck-Condon (FC) region of the ion. Our focus has been on the final state populations of the resulting N and H atoms. The neutral DR fragments are detected downstream of a merged electron and ion beam interaction zone in the TSR storage ring, which is located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Transverse fragment distances were measured on a recently developed high count-rate imaging detector. The distance distributions enabled a detailed tracking of the final state populations as a function of the electron collision energy. These can be correlated with doubly excited neutral states in the FC region of the ion. At low electron energy of similar to 5 eV, the atomic product final levels are nitrogen Rydberg states together with ground-state hydrogen. In a small electron energy interval near 7 eV, a significant part of the final state population forms hydrogen Rydberg atoms with nitrogen atoms in the first excited (D-2) term, showing the effect of Rydberg doubly excited states below the predicted 2(2)Pi ionic potential. The distance distributions above similar to 10 eV are compatible with nitrogen Rydberg states correlating to the doubly excited Rydberg state manifold below the ionic 2(4) Sigma(-) level.
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| 34. |
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| 35. |
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| 36. |
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| 37. |
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| 38. |
- Zhaunerchyk, V., et al.
(författare)
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Three-body breakup in the dissociative recombination of the covalent triatomic molecular ion O-3(+)
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:22, s. 223201-
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Tidskriftsartikel (refereegranskat)abstract
- We report the first observation of almost exclusive three-body breakup in the dissociative recombination of a covalent triatomic molecular ion O-3(+). The three-body channel, constituting about 94% of the total reactivity, has been investigated in detail. The atomic fragments are formed in only the first two electronic states, P-3 and D-1, while formation in the S-1 state has not been observed. The breakup predominantly proceeds through dissociative states with linear geometry.
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| 39. |
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| 40. |
- Carrascosa, E., et al.
(författare)
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Nucleophilic substitution with two reactive centers : The CN- + CH3I case
- 2015
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 143:18
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Tidskriftsartikel (refereegranskat)abstract
- The nucleophilic substitution reaction CN- + CH3I allows for two possible reactive approaches of the reactant ion onto the methyl halide, which lead to two different product isomers. Stationary point calculations predict a similar shape of the potential and a dominant collinear approach for both attacks. In addition, an H-bonded pre-reaction complex is identified as a possible intermediate structure. Submerged potential energy barriers hint at a statistical formation process of both CNCH3 and NCCH3 isomers at the experimental collision energies. Experimental angle-and energy differential cross sections show dominant direct rebound dynamics and high internal excitation of the neutral product. No distinct bimodal distributions can be extracted from the velocity images, which impedes the indication of a specific preference towards any of the product isomers. A forward scattering simulation based on the experimental parameters describes accurately the experimental outcome and shows how the possibility to discriminate between the two isomers is mainly hindered by the large product internal excitation.
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| 41. |
- Geppert, W D, et al.
(författare)
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Dissociative recombination of C3H4+ : preferential formation of the C3H3 radical
- 2004
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806 .- 1873-2798. ; 237:1, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of C3H4+ using the CRYRING ion storage ring. The pre-eminent channel involves the production of C3H3 and H, whereas processes involving rupture of carbon-carbon bonds are clearly disfavoured. The cross section of the reaction could be fitted to the expression sigma = 5.5 +/- 0.2 x 10(-15) E-1.01+/-0.02, which leads to a thermal reaction rate of k(T) = 2.95 +/- 0.1 x 10(-6) (T/300)(-0.67+/-0.02) cm(3) s(-1).
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| 42. |
- Geppert, W. D., et al.
(författare)
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Dissociative recombination of N2H+ : Evidence for fracture of the N-N bond
- 2004
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 609:1, s. 459-464
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of N2H+ using the CRYRING ion storage ring. It has been found that the channel N2H+ + e(-) --> N-2 + H accounts for only 36% of the total reaction and that the branching into the other exoergic pathway, N2H+ + e(-) --> NH + N, consequently amounts to 64%. The cross section of the reaction could be fitted by the expression sigma = (2.4 +/- 0.4) x 10(-16) E-1.04 +/- 0.02 cm(2), which leads to a thermal reaction rate of k(T) = (1.0 +/- 0.2) x 10(-7)(T/300)(-0.51 +/- 0.02) cm(3) s(-1), in favorable agreement with previous flowing afterglow Langmuir probe measurements at room temperature, although our temperature dependence is very different. The implications of these measurements for the chemistry of interstellar clouds are discussed. A standard model calculation for a dark cloud predicts a slight increase of N2H+ in the dark clouds but a five- to sevenfold increase of the NH concentration as steady state is reached.
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| 43. |
- Geppert, W D, et al.
(författare)
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Dissociative recombination of N2OD
- 2004
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 6:13, s. 3415-3419
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of N2OD+ using the CRYRING ion storage ring. The most dominating pathways were found to be those eading to N-2 + OD (46%) and the three-body break-up producing N-2 + O + D (40%). The production of N2O is not observed. The cross section of the reaction could be fitted to the expression sigma = 1.25 +/- 0.25 x 10(-15)(E/eV)(-1.24+/-0.02), which leads to a thermal reaction rate of k(T) = 1.4 +/- 0.1 x 10(-6)(T/300)(-0.74+/-0.02) cm(3) s(-1). The findings are compared with those of the related dissociative recombination of DOCO+ as well as with earlier flowing afterglow measurements.
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| 44. |
- Geppert, W D, et al.
(författare)
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Extraordinary branching ratios in astrophysically important dissociative recombination reactions
- 2004
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Ingår i: Faraday discussions. - : Royal Society of Chemistry (RSC). - 1359-6640 .- 1364-5498. ; 127, s. 425-437
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios of the dissociative recombination reactions of the astrophysically relevant ions DCO+, N2H+ and DOCO+ ( as substitute for HOCO+) have been measured using the CRYRING storage ring at the Manne Siegbahn Laboratory at the University of Stockholm, Sweden. For DCO+, the channel leading to D and CO was by far the most important one ( branching ratio 0.88), only small contributions of the CD+O and OD+C product pathways ( branching ratios 0.06 each) were recorded. In the case of N2H+ the surprising result of a break-up of the N-N bond to N and NH ( branching ratio 0.64) was found with the branching ratio of the N-2+H product channel therefore displaying a branching ratio of only 0.36. In the case of DOCO+, the three-body break-up into D+O+CO dominated ( branching ratio 0.68), whereas the contribution of the CO2+H channel was only minute (0.05). The remaining share ( branching ratio 0.27) was taken by the pathway leading to OH+CO. For the dissociative recombination of N2H+ and DOCO+ also absolute reaction cross sections were obtained in the collisional energy range between 0 and 1 eV. From these cross sections it was possible to work out the thermal rate constants, which were found to be k(T) = 1.0 +/- 0.1 x 10(-7) (T/300 K)(-0.51 +/- 0.02) cm(3) s(-1) and k(T) = 1.2 +/- 0.1 x 10(-6) (T/300 K)(-0.64 +/- 0.02) cm(3) s(-1) for N2H+ and DOCO+, respectively.
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| 45. |
- Hess, Timo, et al.
(författare)
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Dissecting the genetic heterogeneity of gastric cancer
- 2023
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Ingår i: EBioMedicine. - : Elsevier. - 2352-3964. ; 92
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Gastric cancer (GC) is clinically heterogenous according to location (cardia/non-cardia) and histopathology (diffuse/intestinal). We aimed to characterize the genetic risk architecture of GC according to its subtypes. Another aim was to examine whether cardia GC and oesophageal adenocarcinoma (OAC) and its precursor lesion Barrett's oesophagus (BO), which are all located at the gastro-oesophageal junction (GOJ), share polygenic risk architecture.Methods: We did a meta-analysis of ten European genome-wide association studies (GWAS) of GC and its subtypes. All patients had a histopathologically confirmed diagnosis of gastric adenocarcinoma. For the identification of risk genes among GWAS loci we did a transcriptome-wide association study (TWAS) and expression quantitative trait locus (eQTL) study from gastric corpus and antrum mucosa. To test whether cardia GC and OAC/BO share genetic aetiology we also used a European GWAS sample with OAC/BO.Findings: Our GWAS consisting of 5816 patients and 10,999 controls highlights the genetic heterogeneity of GC according to its subtypes. We newly identified two and replicated five GC risk loci, all of them with subtype-specific association. The gastric transcriptome data consisting of 361 corpus and 342 antrum mucosa samples revealed that an upregulated expression of MUC1, ANKRD50, PTGER4, and PSCA are plausible GC-pathomechanisms at four GWAS loci. At another risk locus, we found that the blood-group 0 exerts protective effects for non-cardia and diffuse GC, while blood-group A increases risk for both GC subtypes. Furthermore, our GWAS on cardia GC and OAC/BO (10,279 patients, 16,527 controls) showed that both cancer entities share genetic aetiology at the polygenic level and identified two new risk loci on the single-marker level.Interpretation: Our findings show that the pathophysiology of GC is genetically heterogenous according to location and histopathology. Moreover, our findings point to common molecular mechanisms underlying cardia GC and OAC/BO.
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| 46. |
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| 47. |
- Novotny, O., et al.
(författare)
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Dissociative Recombination Measurements of Chloronium Ions (D2Cl+) Using an Ion Storage Ring
- 2018
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 862:2
-
Tidskriftsartikel (refereegranskat)abstract
- We report our plasma rate coefficient and branching ratio measurements for dissociative recombination (DR) of D2Cl+ with electrons. The studies were performed in a merged-beams configuration using the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Starting with our absolute merged-beams recombination rate coefficient at a collision energy of approximate to 0 eV, we have extracted the cross section and produced a plasma rate coefficient for a translational temperature of approximate to 8 K. Furthermore, extrapolating our cross-section results using the typical low-energy DR behavior, we have generated a plasma rate coefficient for translational temperatures from 5 to 500 K. We find good agreement between our extrapolated results and previous experimental DR studies on D2Cl+. Additionally, we have investigated the three fragmentation channels for DR of D2Cl+. Here we report on the dissociation geometry of the three-body fragmentation channel, the kinetic energy released for each of the three outgoing channels, the molecular internal excitation for the two outgoing channels that produce molecular fragments, and the fragmentation branching ratios for all three channels. Our results, in combination with those of other groups, indicate that any remaining uncertainties in the DR rate coefficient for H2Cl+ appear unlikely to explain the observed discrepancies between the inferred abundances of HCl and H2Cl+ in molecular clouds and predictions from astrochemical models.
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| 48. |
- Thomas, Richard D., et al.
(författare)
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Dissociative recombination of LiH2
- 2014
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 89:5, s. 050701-
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we report results regarding how LiH2+ fragments as a result of a low-energy collision with an electron (dissociative recombination), a reaction that contains only elements and particles created during the very first phase of the universe. The collision-energy-dependent reaction rate and cross sections show detailed structures, more so than predicted by theory, suggesting significant rovibrational coupling in the ion and a complex reaction surface. From the structure of the molecule, the reaction predominantly results in the formation of Li + H-2. However, 23% of the reaction flux leads to more interesting products, with 17% producing Li + 2H and 6% producing LiH + H. These last two channels break the strongest molecular bond in the system and, in the case of the latter channel, form a significantly weaker ionic bond. Possible reasons behind this interesting behavior are discussed, together with the interaction between the available reaction channels.
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| 49. |
- Viggiano, A. A., et al.
(författare)
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Rate constants and branching ratios for the dissociative recombination of CO2
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 122:22, s. 226101-
-
Tidskriftsartikel (refereegranskat)abstract
- The calculation of rate constants and branching ratios was carried out to study the dissociative recombination of CO2+. The recombination of CO2+ is significant in the atmospheres of Venus and Mars. Rate constants and cross sections were studied by ramping the electron beam around a center-of-mass energy of 0 eV. The results of the study confirms that all the recombination of CO2+ results in a simple bondbreaking to form CO plus O. The rate constants show good agreement with measurements at 300 K and the electron energy dependence is identical to storage ring results.
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| 50. |
- Zhaunerchyk, Vitali, et al.
(författare)
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Dissociative recombination of D2H+ : Comparison between recent storage-ring results and theoretical calculations
- 2008
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 77:3, s. 34701-
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Tidskriftsartikel (refereegranskat)abstract
- The most up-to-date theoretical calculation on the dissociative recombination (DR) of D2H+ predicts a 2-5 times lower rate coefficient than that obtained experimentally at the Test Storage Ring (TSR). In order to verify the validity either of the experimental results or the theoretical calculations we have studied the DR of D2H+ at the storage ring CRYRING. The rate coefficient has been measured over the interaction energy range from approximate to 0 eV to 50 eV and has been found to have a peak at about 10 eV with a value of 1.6 x 10(-8) cm(3) s(-1), which is in excellent agreement with the result reported from TSR. Taking into account the electron temperature distributions, excellent agreement between the two storage rings measurements is also obtained at smaller interaction energies. The branching fraction analysis has been performed at approximate to 0 eV interaction energy and revealed the following results at the 1 sigma confidence level: N(D+D+H)=76.5%+/-2.2%, N(D-2+H)= 10.0%+/-0.7%, and N(DH+D)=13.5%+/-1.5%. The value of 2N(D-2+H)/N(DH+D)=1.48+/-0.22 implies that formation of D-2 is more favorable than DH.
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