| 1. |
- Abazov, V. M., et al.
(författare)
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The upgraded DO detector
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
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Tidskriftsartikel (refereegranskat)abstract
- The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
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| 2. |
- Abazov, V. M., et al.
(författare)
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Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV using secondary vertex b tagging
- 2006
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-7998 .- 1550-2368. ; 74:11, s. 112004-
-
Tidskriftsartikel (refereegranskat)abstract
- We report a new measurement of the t (t) over bar production cross section in p (beta) over bar collisions at a center-of-mass energy of 1.96 TeV using events with one charged lepton (electron or muon), missing transverse energy, and jets. Using 425 pb(-1) of data collected using the D0 detector at the Fermilab Tevatron Collider, and enhancing the t (t) over bar content of the sample by tagging b jets with a secondary vertex tagging algorithm, the t (t) over bar production cross section is measured to be sigma(p (t) over bar -> t (t) over bar +X)=6.6 +/- 0.9(stat+syst) +/- 0.4(lum) pb. This cross section is the most precise D0 measurement to date for t (t) over bar production and is in good agreement with standard model expectations.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Bäcktorp, Carina, 1964, et al.
(författare)
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Theoretical investigation of linalool oxidation.
- 2006
-
Ingår i: The journal of physical chemistry. A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:44, s. 12204-12
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Tidskriftsartikel (refereegranskat)abstract
- This study concerns the autoxidation of one of the most used fragrances in daily life, linalool (3,7-dimethyl-1,6-octadien-3-ol). It reacts with O2 to form hydroperoxides, which are known to be important contact allergens. Pathways for hydroperoxide formation are investigated by means of quantum mechanical electronic structure calculations. Optimized molecular geometries and harmonic vibrational frequencies are determined using density functional theory (DFT). Insight into how the addition of O2 to linalool occurs is obtained by establishing a theoretical framework and systematically investigating three smaller systems: propene, 2-methyl-2-butene, and 2-methyl-2-pentene. 2-Methyl-2-pentene was chosen as a model system and used to compare with linalool. This theoretical study characterizes the linalool-O2 biradical intermediate state, which constitutes a branching point for the further oxidation reactions pathways. Thus, the observed linalool oxidation product spectrum is discussed in terms of a direct reaction path, the ene-type mechanism, and the radical mechanism. The major hydroperoxide found in experiments is 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol, and the calculated results support this finding.
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| 8. |
- Cain, Peter, et al.
(författare)
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Physiological determinants of the variation in left ventricular mass from early adolescence to late adulthood in healthy subjects
- 2005
-
Ingår i: Clin Physiol Funct Imaging. - 1475-0961. ; 25:6, s. 332-9
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The physiological determinants of left ventricular mass (LVM) measured by cardiac magnetic resonance (CMR) imaging are not well defined as prior investigators have studied either adults or adolescents in isolation or have not strictly excluded hypertension or accounted for the effects of exercise habits, haemodynamic, demographic, or body shape characteristics. METHODS: A total of 102 healthy volunteers (12-81 years, 53 males) underwent CMR. All parameters [unstandardized and adjusted for body surface area (BSA)] were analysed according to gender and by adolescence versus adulthood (adolescents <20 years, adults > or = 20 years). The influence of haemodynamic factors, exercise, and demographic factors on LVM were determined with multivariate linear regression. Results: LVM rose during adolescence and declined in adulthood. LVM and LVMBSA were higher in males both in adults (LVM: 188 +/- 22 g versus 139 +/- 21 g, P < 0.001; LVMBSA: 94 +/- 11 g m(-2) versus 80 +/- 11 g m(-2), P < 0.001) and in adolescents when adjusted for BSA (LVM: 128 +/- 29 g versus 107 +/- 20 g, P = 0.063; LVMBSA: 82 +/- 8 g m(-2) versus 71 +/- 10 g m(-2), P = 0.025). In adults, systolic blood pressure (SBP) and self-reported physical activity increased while meridional and circumferential wall stress were constant with age. Multivariate regression analysis revealed age, gender, and BSA as the major determinants of LVM (global R2 = 0.69). CONCLUSIONS: Normal LVM shows variation over a broad age range in both genders with a rise in adolescence and subsequent decline with increasing age in adulthood despite an increase in SBP and physical activity. BSA, age, and gender were found to be major contributors to the variation in LVM in healthy adults, while haemodynamic factors, exercise, and wall stress were not.
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| 9. |
- de Vera, Jean Paul, et al.
(författare)
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EUROX (Europa Explorer): An astrobiology mission concept to the Jovian icy moon Europa.
- 2008
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Ingår i: Geophysical Research Abstracts. ; 10, EGU2008-A-01483, 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The discovery of so-called extremophiles indicates how robust life is. That microbial life can resist extreme and harsh environmental conditions as e.g. very high and cold temperatures, desiccation, acidity, salinity and wide ranges of radiation spectra including UV and X-rays, suggests that micro organisms are capable of surviving and maintaining essential living functions, or often thriving, in conditions previously thought impossible. Recently it seems that only liquid water and an energy source are the core prerequisites for the development of life, greatly expanding the range of potential habitats for life both on Earth and in the solar system. In light of these discoveries, the definition of the “Habitable Zone” as the region where liquid water can exist at a planetary surface may need revision. Energy in the form of heat may be found on several volcanic worlds in our solar system, and subsurface liquid water may exist there, too. One likely candidate for such a reserve of water is the jovian icy moon Europa. Imaged by the Voyager and Galileo probes, this icy body appears to have a geologically young outer surface. Spectroscopic studies from Earth have confirmed that the European crust is composed of water ice. Long cracks across its surface may be suggestive of huge ice blocks rafting upon an underlying liquid layer. Darker non ice material also covers much of the surface and is spatially associated with the cracks. Recent modeling suggests that tidal forces imparted upon the moon by Jupiter may cause heating in the depth – raising the possibility of a liquid water ocean beneath Europa’s icy crust. Further on it is supposed that a weak induced magnetic field is present on the moon. This classifies Europa as an object of great scientific interest, warranting investigation for habitability and even the presence of life within the supposed ocean of the moon. The Europa Explorer (EUROX) mission complements other proposed missions to study Europa. EUROX will characterize the habitability potential of Europa, with the aim of understanding whether life could exist there or not. The mission will address the following key questions: (i) existence or non- existence of a liquid ocean beneath the surface, (ii) the nature of the non icy material visible upon the surface cracks, (iii) the physical characteristics of the ice crust, (iv) effects by local radiation on the surface chemistry, (v) the depth of radiation penetration in the ice and probably shielding effects by a magnetic field and (vi) the presence of organic compounds on or in the Europan ice crust. Our proposed mission will operate as a fully European and further on international mission, with the aim of providing the initial information required for later, larger missions to visit Europa. EUROX will involve both remote-sensing and in-situ research. Its mission architecture sees a single space craft deployed to Europa, launched by an Ariane 5. This vehicle will use conventional propulsion and a Venus-Earth-Earth flight path to travel to the jovian system in six years. Upon arrival at Europa, the space craft will commence remote observations of the icy moon, to determine the physical nature of the ice crust, and to investigate the presence of a subsurface liquid ocean. The orbiter will carry two independent vehicles (two penetrators) that will then separate, de-orbit, and penetrate the crust nearby or in the cracks to a depth of several meters. A suite of compact instruments will address the physical and chemical properties of the crust, as well as seeking organic compounds and pre-biotic material in the ice. The use of a laser communication system removes the need for a relay spacecraft in orbit around Jupiter, decreasing overall mission cost. Expected orbiter mission duration is on the order of two months, with each penetrator functioning for approximately 24 hours.
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| 10. |
- Devlin, R. H., et al.
(författare)
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Assessing Phenotypic and Ecological Effects of Transgenic Fish Prior to Entry into Nature.
- 2007
-
Ingår i: Kapuscinski, A.R., K.R. Hayes, S. Li and G. Dana (eds). (E.M. Hallerman and P.J. Schei, series editors). 2007. Environmental Risk Assessment of Genetically Modified Organisms, Vol 3: Methodologies for Transgenic Fish. - Cambridge, MA, USA : CABI. - 9781845932961 ; , s. 151-187
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 11. |
- Faergemann, Jan, 1948, et al.
(författare)
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Pentane-1,5-diol as a percutaneous absorption enhancer
- 2005
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Ingår i: Arch Dermatol Res. - : Springer Science and Business Media LLC. ; 297:6, s. 261-5
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Tidskriftsartikel (refereegranskat)abstract
- Propylene glycol (propane-1,2-diol) is the only diol widely used in dermatology. Pentane-1,5-diol is mainly used as a plasticizer in cellulose products and adhesives, in dental composites and in brake fluid compositions and as a preservative for grain. However, pentane-1,5-diol is also an effective solvent, water-binding substance, antimicrobial agent and preservative and may therefore replace several ingredients in a skin composition. The release of tri-iodothyroacetic acid (TRIAC) and percutaneous absorption of hydrocortisone and mometasone furoate with either pentane-1,5-diol or propane-1,2-diol and 2-methyl-pentane-2,4-diol (hexylene glycol), respectively, as enhancers was compared. The release of TRIAC was 21% higher when pentane-1,5-diol was used as an enhancer instead of propane-1,2-diol. The percutaneous absorption of hydrocortisone through the skin was increased 12 times with propane-1,2-diol compared to 4.4 times with pentane-1,5-diol. However, the percutaneous absorption of hydrocortisone into the skin was 50% higher with pentane-1,5-diol compared to propane-1,2-diol. There was no significant difference, between the original mometasone furoate cream, with 2-methyl-pentane-2,4-diol, and the new cream with pentane-1,5-diol in the amount of mometasone furoate that was absorbed into the skin and through the skin. However, the cosmetic properties of the new mometasone furoate cream was superior to the original mometasone furoate cream, for examples, no bad odour, more even texture, goes better into the skin and has less greasiness. Pentane-1,5-diol can be used as a technology platform, which adds a series of desirable properties to dermatological preparations and enhances product usability. This will result in improved formulations for a series of major and commonly used dermatological drugs. When used in pharmaceutical topical preparations, pentane-1,5-diol will increase the percutaneous absorption of the active substance and it is an efficient antimicrobial agent that will act as an effective preservative in topical formulations. Pentane-1,5-diol is cosmetically attractive, has low risk for skin and eye irritation compared to other diols, low toxicity risk and no bad odour.
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| 12. |
- Hagelin, Christina, 1977, et al.
(författare)
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A polarized-light spectroscopy study of interactions of a hairpin polyamide with DNA
- 2006
-
Ingår i: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 91:3, s. 904-911
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Tidskriftsartikel (refereegranskat)abstract
- We here study the interactions of a polyamide with large DNA, and compare to those of minor groove binder distamycin (DST), including high ligand/DNA binding ratios. Specific as well as nonspecific binding is probed using polarized-light spectroscopy combined with singular value decomposition analysis. Circular and linear dichroism data confirm binding geometries consistent with minor groove binding for both of the ligands. Interestingly, at high and intermediate ligand/DNA ratios the polyamide exhibits no significant sequence discrimination between mixed-sequence (calf thymus) and AT DNA as compared to DST. Each ligand is concluded to exhibit two different binding modes depending upon ligand/DNA ratio and nucleo-base sequence. At high binding ratios, distinct differences between the ligands are observed: circular dichroism spectra exciton effects provide evidence of bimolecular interactions of the polyamide when bound to AT-DNA, whereas no effects are seen with DST or mixed-sequence DNA. Also linear dichroism indicates that a change in binding geometry occurs at high polyamide/AT ratios, and that the effect occurs only with polyamide in contrast to DST. Since the effect is insignificant with DST, or with calf thymus DNA, it is concluded that it relates to the sizes of the ligands and the minor grooves, becoming critical in the limit of crowding.
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| 13. |
- Hauber, Ernst, et al.
(författare)
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MORPHOMETRY OF ALLUVIAL FANS IN A POLAR DESERT (SVALBARD, NORWAY): IMPLICATIONS FOR INTERPRETING MARTIAN FANS.
- 2009
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Ingår i: 40th Lunar and Planetary Science Conference. ; :1648
-
Konferensbidrag (refereegranskat)abstract
- Alluvial fan-like landforms have been identified on Mars. Since alluvial fans are recorders of processes that are sensitive to climatic conditions, the investigation of possible Martian fans can reveal information about the planet`s climate. In lieu of direct observations of active depositional processes on Martian fans, comparisons with terrestrial analogues can constrain models of Martian fan formation derived from remote sensing data. Since present-day Mars is cold and dry, alluvial fans formed in cold deserts should be considered as useful analogues. The probably closest climatic analogue to Mars on Earth are the Antarctic Dry Valleys , but polar deserts can also be found in the Arctic. We report on our field work in summer 2008 and a simultaneous flight campaign with an airborne version (HRSC-AX) of the High Resolution Stereo Camera (HRSC) onboard Mars Express. The results are compared with measurements of Martian fans, based on HRSC DEM.
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| 14. |
- Hauber, Ernst, et al.
(författare)
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Svalbard (Norway) as a terrestrial analogue for Martian landforms: Results on
- 2009
-
Ingår i: EPSC Abstracts. European Planetary Science Congress. ; 4, EPSC2009-772
-
Konferensbidrag (refereegranskat)abstract
- Small alluvial fan-like landforms have been observed on Mars in association with recent gullies. Such fans are relatively small (km-scale) when compared to large alluvial fans on Mars, which can reach dimensions of tens of kilometers. The small fans are part of an erosion-transportsedimentation system (alcove-channel-apron). Morphologically very similar systems can be studied on Svalbard (Norway), which is a cold and dry polar desert and, therefore, a potentially useful terrestrial analogue for Mars` climate and climaterelated landforms. Here we give an update on our field work in summer 2008 and a simultaneous flight campaign with an airborne version (HRSCAX) of the High Resolution Stereo Camera (HRSC) onboard Mars Express. We also present very preliminary results from the field campaign in summer 2009.
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| 15. |
- Johnsson, Per, et al.
(författare)
-
Attosecond electron wave packet dynamics in strong laser fields
- 2005
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Ingår i: Physical Review Letters. - 1079-7114. ; 95:1, s. 1-013001
-
Tidskriftsartikel (refereegranskat)abstract
- We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy (similar to 20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes.
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| 16. |
- Johnsson, Per, et al.
(författare)
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Trains of attosecond electron wave packets
- 2006
-
Ingår i: Journal of Modern Optics. - : Informa UK Limited. - 0950-0340 .- 1362-3044. ; 53:1-2, s. 233-245
-
Tidskriftsartikel (refereegranskat)abstract
- We study temporally localized electron wave packets, generated using a train of extreme ultraviolet (XUV) attosecond pulses to ionize the target atoms. Both the electron wave packets and the attosecond pulse train ( APT) are characterized using the same technique, based on interference of two-photon transitions in the continuum. We study, in particular, the energy transfer from a moderately strong infrared (IR) field to the electron wave packets as a function of time delay between the XUV and the IR fields. The use of an APT to generate the electron wave packets enables the generation at times not accessible through tunneling ionization. We find that a significant amount of energy is transferred from the IR field to the electron wave packets, when they are generated at a zero-crossing of the IR laser field. This energy transfer results in a dramatically enhanced above-threshold ionization even at IR intensities that alone are not strong enough to induce any significant ionization.
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| 17. |
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| 18. |
- Johnsson Wass, J R Tobias, et al.
(författare)
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Quantum chemical modeling of the reduction of quinones.
- 2006
-
Ingår i: The journal of physical chemistry. A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:5, s. 2005-20
-
Tidskriftsartikel (refereegranskat)abstract
- A systematic study of the redox properties of six parent quinones has been carried out using quantum chemistry methods. The reduction of the ortho (o-) and para (p-) isomers of benzoquinone and naphthoquinone, 9,10- anthraquinone and 9,10-phenantrenequinone to the corresponding hydroquinones and semiquinone radicals was investigated at the B3LYP/6-311+G(d,p) level of theory. Thermodynamic functions in the gas-phase were calculated for all the reduction reactions. Gibbs energies of reaction and standard potentials in water for the reductions were determined using the IEF-PCM model and an empirical correction to the calculations based on the limited thermodynamic data available for the quinones. Potentials were calculated both for the direct reduction to the quinols, and for the two-step reduction via the neutral semiquinones. The calculated potentials for the 2e-, 2H+ reductions were found in good agreement with experiment and to display the same trends as gas-phase enthalpies and energies, i.e., to correlate with the number of C=C double bonds, as well as on the relative position of the C=O groups. The small deviations between experiment and theoretically predicted standard potentials were found to originate from basis set incompleteness and the shortcomings in the B3LYP exchange correlation functional rather than the models used for the thermochemical calculations or description of solvation. Accurate theoretical shifts in standard potentials for the p-/o- pairs of Q <--> HQ and HQ <--> H2Q reactions are presented and compared to experiment. Reliable standard potentials and shifts for the neutral semiquinones are predicted for the first time.
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| 19. |
- Johnsson Wass, J R Tobias, et al.
(författare)
-
Quantum chemical modelling of oxygen reduction on cobalt hydroxide and oxyhydroxide
- 2007
-
Ingår i: Journal of Electroanalytical Chemistry. - : Elsevier BV. - 1572-6657. ; 599:2, s. 295-312
-
Tidskriftsartikel (refereegranskat)abstract
- Quantum chemistry has been employed to analyse the experimentally observed production of H2O2 during electrochemical reduction of O-2 on cobalt oxyhydroxide, CoOOH(s). The site for O-2 reduction was modelled using both small hydrated Co hydroxide clusters and periodic slab models of a step edge site. A catalytic site was found for the Co(II) model cluster, Co(OH)(2)(H2O)(7), which was also found in the step edge models. However, the site was found to bind O-3(2) very loosely and the Co(II) site alone displayed no electron affinity. The reduction reaction was initiated by adding an electron with O-2 present at the Co(II) site. This produces a superoxide ligand, which upon protonation is able to undergo further reduction to HO2- as Co(III) is formed at the site. Adding a second electron leads to detachment of HO2- as Co(II) is restored. A catalytic redox cycle is presented based on this understanding. The reduction behaviour explains why O-2 is readily reduced on p-type CoOOH at potentials where H2O2 is reduced at a low rate only. O-2 has the ability to introduce new charge carriers into the electrode, which means that the current is limited by charge transfer kinetics and not the electrical properties of the electrode material. H2O2 cannot produce additional charge carriers, and the electrode material limits the current.
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| 20. |
- Johnsson Wass, J R Tobias, et al.
(författare)
-
Quantum chemical modelling of the rate determining step for oxygen reduction on quinones.
- 2006
-
Ingår i: Physical chemistry chemical physics : PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 8:36, s. 4189-99
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Tidskriftsartikel (refereegranskat)abstract
- Two inner-sphere electrocatalytic channels for quinone-mediated reduction of molecular oxygen to form hydrogen peroxide have been addressed by means of density functional theory. Each of the channels comprises an initial rate determining chemical step and a subsequent electrochemical reduction step by which peroxide is produced. The reduction mechanism was determined for 9,10-anthraquinone and 9,10-phenanthrenequinone and the quantum chemical results are compared with experimental results. Two distinctly different structures were determined for the critical chemical step depending on whether the catalytic site is present as HQ* or Q*-. While a superoxo species is formed on HQ*, a van der Waals (vdW) type compound is formed on Q*-. It is shown that the Gibbs energy of activation for the semiquinone/oxygen reaction is largely determined by the entropy term. The results explain the experimentally observed pH dependence of the O2 reduction rate on quinone functionalised electrodes.
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| 21. |
- L'Huillier, A., et al.
(författare)
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Atomic physics with attosecond pulses
- 2006
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Ingår i: International Conference on Ultrafast Phenomena, UP 2006. - 1557528101 - 9781557528100
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Konferensbidrag (refereegranskat)
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| 22. |
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| 23. |
- Neregård, Lena, 1973, et al.
(författare)
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Wild Atlantic salmon Salmo salar L. strains have greater growth potential than a domesticated strain selected for fast growth
- 2008
-
Ingår i: Journal of Fish Biology. - : Wiley. - 1095-8649 .- 0022-1112. ; 73:1, s. 79-95
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Tidskriftsartikel (refereegranskat)abstract
- A study was undertaken to examine the responses of three Atlantic salmon Salmo salar strains to growth hormone (GH) treatment. A positive growth response to sustained-release GH implants was found in two wild strains (Namsen and Imsa) as well as one domesticated strain (AquaGen). The data revealed that the growth-selected AquaGen strain has further growth potential, however, a stronger growth response was observed in the wild strains which outgrew the domesticated strain after GH treatment. These observations suggest that some growth potential may have been lost during the selection for rapid growth in the AquaGen strain. In September, the parr were GH implanted and in December sampled for plasma GH and insulin-like growth factor I (IGF-I) levels, liver, muscle and gill GH receptor, IGF-I mRNA levels, gill Na+,K+-ATPase activity, muscle and liver lipid content and body silvering. Low temperature and seasonal growth cessation probably explains the relatively limited GH effects found. Body silvering in all strains was positively correlated to size. GH increased IGF-I plasma levels in the Namsen strain inspite of liver IGF-I mRNA levels being lower in GH-treated fish.
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| 24. |
- Remetter, Thomas, et al.
(författare)
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Attosecond electron wave packet interferometry
- 2006
-
Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2473 .- 1745-2481. ; 2:5, s. 323-326
-
Tidskriftsartikel (refereegranskat)abstract
- A complete quantum-mechanical description of matter and its interaction with the environment requires detailed knowledge of a number of complex parameters. In particular, information about the phase of wavefunctions is important for predicting the behaviour of atoms, molecules or larger systems. In optics, information about the evolution of the phase of light in time(1) and space(2) is obtained by interferometry. To obtain similar information for atoms and molecules, it is vital to develop analogous techniques. Here we present an interferometric method for determining the phase variation of electronic wave packets in momentum space, and demonstrate its applicability to the fundamental process of single-photon ionization. We use a sequence of extreme-ultraviolet attosecond pulses(3,4) to ionize argon atoms and an infrared laser field, which induces a momentum shear(5) between consecutive electron wave packets. The interferograms that result from the interaction of these wave packets provide useful information about their phase. This technique opens a promising new avenue for reconstructing the wavefunctions(6,7) of atoms and molecules and for following the ultrafast dynamics of electronic wave packets.
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| 25. |
- Retegan Vollmer, Teodora, 1979, et al.
(författare)
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Extraction of actinides with different 6,60-bis(5,6-dialkyl-[1,2,4]-triazin-3-yl)[2,20]-bipyridines (BTBPs)
- 2007
-
Ingår i: SOLVENT EXTRACTION AND ION EXCHANGE. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 25:4, s. 417-431
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Tidskriftsartikel (refereegranskat)abstract
- The extraction of Am(III), Th(IV), Np(V), and U(VI) from nitric acid by 6,6′‐bis(5,6‐dialkyl‐[1,2,4]‐triazin‐3‐yl)‐[2,2′]‐bipyridines (C2‐, C4‐, C5‐, and CyMe4‐BTBP) was studied. Since only americium and neptunium extraction was dependent on the BTBP concentration, computational chemistry was used to explain this behavior. It has been shown that the coordination of the metal played an important role in forming an extractable complex into the organic phase, thus making it possible to extract pentavalent and trivalent elements from tetravalent and hexavalent elements. This is very important, especially because it shows other possible utilizations of a group of molecules meant to separate the actinides from the lanthanides. In addition, the level of extraction at very low or no BTBP concentration was explained by coordination chemistry.
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| 26. |
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| 27. |
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| 28. |
- Sundström, L. Fredrik, 1972, et al.
(författare)
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Dispersal potential is affected by growth-hormone transgenesis in coho salmon (Oncorhynchus kisutch).
- 2007
-
Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 113:4, s. 403-410
-
Tidskriftsartikel (refereegranskat)abstract
- Potential ecological consequences on the natural environment of fast-growing transgenic fish with elevated intrinsic growth rates is an important question should such fish be allowed in commercial production systems. One trait that will strongly affect the spatial extent of consequences is the propensity of transgenic fish to disperse. We addressed this question in three experiments using different measures of spatial dispersal where we compared very young genotypically wild coho salmon with transgenic conspecifics in terms of: (i) group cohesion, (ii) exploratory behavior, and (iii) up- and downstream movements. Transgenic fish were more loosely aggregated, more likely to explore, and less likely to swim upstream, but equally likely to disperse downstream compared with genetically wild fish. These results show that dispersal behavior has been affected by transgenesis and that transgenic fish therefore may venture into habitats previously not used by wild fish. Given the importance of dispersal in ecological risk-assessment of transgenic fish, continued work within this area is warranted and experimental habitats should mimic the potential receiving natural habitats to which transgenic fish are likely to escape or be released to.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Takagi, R, et al.
(författare)
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MoCu3TeO7Cl2 center dot 0.5H(2)O
- 2006
-
Ingår i: Acta Crystallographica Section C-Crystal Structure Communications. ; 62, s. 116-118
-
Tidskriftsartikel (refereegranskat)
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| 33. |
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| 34. |
- Varju, Katalin, et al.
(författare)
-
Attosecond dynamics of electron wave packets in intense laser fields
- 2007
-
Ingår i: Ultrafast Optics V (Springer Series in Optical Sciences). - 0342-4111. - 9780387491172 ; 132, s. 15-24
-
Konferensbidrag (refereegranskat)abstract
- We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy (∼20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes.
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| 35. |
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| 36. |
- Zaïr, A., et al.
(författare)
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Confinement of attosecond train pulses by using a modulated polarization IR pulse
- 2005
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Ingår i: 2005 Conference on Lasers and Electro-Optics Europe. - 0780389743 - 9780780389748
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Konferensbidrag (refereegranskat)abstract
- We study the temporal and spectral behaviour of high order harmonics generated by pulses with temporally modulated polarization. We observe a harmonic temporal confinement and a harmonic spectral broadening, compatible with 1 -or-2 attosecond pulse emission.
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| 37. |
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