| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
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| 5. |
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| 6. |
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| 7. |
- 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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| 8. |
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| 9. |
- 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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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Biester, EM, et al.
(författare)
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Identification of avian wax synthases
- 2012
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Ingår i: BMC biochemistry. - : Springer Science and Business Media LLC. - 1471-2091. ; 13, s. 4-
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Tidskriftsartikel (refereegranskat)
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| 17. |
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| 18. |
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Hamberg, Eva, et al.
(författare)
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Utbud och efterfrågan på religiösa "marknader"
- 2002
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Ingår i: Religion och sociologi : ett fruktbart möte : festskrift till Göran Gustafsson (Religio, ISSN: 0280-5723 ; 55). - 0280-5723.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 23. |
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| 24. |
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| 25. |
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| 26. |
- Hellenbrand, J, et al.
(författare)
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Fatty acyl-CoA reductases of birds
- 2011
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Ingår i: BMC biochemistry. - : Springer Science and Business Media LLC. - 1471-2091. ; 12, s. 64-
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Tidskriftsartikel (refereegranskat)
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| 27. |
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| 28. |
- Kneeshaw, S, et al.
(författare)
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Ligand diversity contributes to the full activation of the jasmonate pathway in Marchantia polymorpha
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 119:36, s. e2202930119-
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Tidskriftsartikel (refereegranskat)abstract
- In plants, jasmonate signaling regulates a wide range of processes from growth and development to defense responses and thermotolerance. Jasmonates, such as jasmonic acid (JA), (+)-7-iso-jasmonoyl-l-isoleucine (JA-Ile), 12-oxo-10,15(Z)-phytodienoic acid (OPDA), and dinor-12-oxo-10,15(Z)-phytodienoic acid (dn-OPDA), are derived from C18 (18 Carbon atoms) and C16 polyunsaturated fatty acids (PUFAs), which are found ubiquitously in the plant kingdom. Bryophytes are also rich in C20 and C22 long-chain polyunsaturated fatty acids (LCPUFAs), which are found only at low levels in some vascular plants but are abundant in organisms of other kingdoms, including animals. The existence of bioactive jasmonates derived from LCPUFAs is currently unknown. Here, we describe the identification of an OPDA-like molecule derived from a C20 fatty acid (FA) in the liverwortMarchantia polymorpha(Mp), which we term (5Z,8Z)-10-(4-oxo-5-((Z)-pent-2-en-1-yl)cyclopent-2-en-1-yl)deca-5,8-dienoic acid (C20-OPDA). This molecule accumulates upon wounding and, when applied exogenously, can activate known Coronatine Insensitive 1 (COI1) –dependent and –independent jasmonate responses. Furthermore, we identify a dn-OPDA–like molecule (Δ4-dn-OPDA) deriving from C20-OPDA and demonstrate it to be a ligand of the jasmonate coreceptor (MpCOI1–Mp Jasmonate-Zinc finger inflorescence meristem domain [MpJAZ]) inMarchantia. By analyzing mutants impaired in the production of LCPUFAs, we elucidate the major biosynthetic pathway of C20-OPDA and Δ4-dn-OPDA. Moreover, using a double mutant compromised in the production of both Δ4-dn-OPDA and dn-OPDA, we demonstrate the additive nature of these molecules in the activation of jasmonate responses. Taken together, our data identify a ligand of MpCOI1 and demonstrate LCPUFAs as a source of bioactive jasmonates that are essential to the immune response ofM. polymorpha.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
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| 36. |
- Novotny, O., et al.
(författare)
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Dissociative Recombination Measurements of Chloronium Ions (D2Cl+) Using an Ion Storage Ring
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 862:2
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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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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Vellosillo, T, et al.
(författare)
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Defense activated by 9-lipoxygenase-derived oxylipins requires specific mitochondrial proteins
- 2013
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Ingår i: Plant physiology. - : Oxford University Press (OUP). - 1532-2548. ; 161:2, s. 617-627
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Tidskriftsartikel (refereegranskat)abstract
- 9-Lipoxygenases (9-LOXs) initiate fatty acid oxygenation, resulting in the formation of oxylipins activating plant defense against hemibiotrophic pathogenic bacteria. Previous studies using nonresponding to oxylipins (noxy), a series of Arabidopsis (Arabidopsis thaliana) mutants insensitive to the 9-LOX product 9-hydroxy-10,12,15-octadecatrienoic acid (9-HOT), have demonstrated the importance of cell wall modifications as a component of 9-LOX-induced defense. Here, we show that a majority (71%) of 41 studied noxy mutants have an added insensitivity to isoxaben, an herbicide inhibiting cellulose synthesis and altering the cell wall. The specific mutants noxy2, noxy15, and noxy38, insensitive to both 9-HOT and isoxaben, displayed enhanced susceptibility to Pseudomonas syringae DC3000 as well as reduced activation of salicylic acid-responding genes. Map-based cloning identified the mutation in noxy2 as At5g11630 encoding an uncharacterized mitochondrial protein, designated NOXY2. Moreover, noxy15 and noxy38 were mapped at the DYNAMIN RELATED PROTEIN3A and FRIENDLY MITOCHONDRIA loci, respectively. Fluorescence microscopy and molecular analyses revealed that the three noxy mutants characterized exhibit mitochondrial dysfunction and that 9-HOT added to wild-type Arabidopsis causes mitochondrial aggregation and loss of mitochondrial membrane potential. The results suggest that the defensive responses and cell wall modifications caused by 9-HOT are under mitochondrial retrograde control and that mitochondria play a fundamental role in innate immunity signaling.
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| 41. |
- Vellosillo, T, et al.
(författare)
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Oxylipins produced by the 9-lipoxygenase pathway in Arabidopsis regulate lateral root development and defense responses through a specific signaling cascade
- 2007
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Ingår i: The Plant cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 19:3, s. 831-846
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Tidskriftsartikel (refereegranskat)abstract
- Arabidopsis thaliana seedling growth with pure oxylipins resulted in root waving, loss of root apical dominance, and decreased root elongation. 9-Hydroxyoctadecatrienoic acid (9-HOT) was a potent inducer of root waving. Studies with noxy2 (for nonresponding to oxylipins2), a new 9-HOT–insensitive mutant, and coronatine insensitive1-1 (jasmonate-insensitive) revealed at least three signaling cascades mediating the oxylipin actions. Treatment with 9-HOT resulted in a reduction in lateral roots and an increase in stage V primordia. Roots showed strong 9-lipoxygenase (9-LOX) activity, and root primordia expressed 9-LOX genes. These results, along with findings that noxy2 and mutants with defective 9-LOX activity showed increased numbers of lateral roots, suggest that 9-HOT, or a closely related 9-LOX product, is an endogenous modulator of lateral root formation. Histochemical and molecular analyses revealed that 9-HOT activated events common to development and defense responses. A subset of 9-HOT–responding root genes was also induced in leaves after 9-HOT treatment or pathogen inoculation. The results that noxy2 displayed altered root development, enhanced susceptibility to Pseudomonas, and reduced the activation of 9-HOT–responding genes are consistent with mechanistic links among these processes. The nature of the changes detected suggests that oxylipins from the 9-LOX pathway function in cell wall modifications required for lateral root development and pathogen arrest.
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| 42. |
- Zhaunerchyk, Vitali, et al.
(författare)
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Dissociative recombination of D2H+ : Comparison between recent storage-ring results and theoretical calculations
- 2008
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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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| 43. |
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| 44. |
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| 45. |
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| 46. |
- Andersson, Mats X., 1977, et al.
(författare)
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Involvement of the Electrophilic Isothiocyanate Sulforaphane in Arabidopsis Local Defense Responses
- 2015
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 167:1
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Tidskriftsartikel (refereegranskat)abstract
- Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue.
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| 47. |
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| 48. |
- Angelova, G., et al.
(författare)
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Observation of two-dimensional longitudinal-transverse correlations in an electron beam by laser-electron interactions
- 2008
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Ingår i: Physical Review Special Topics - Accelerators and Beams. - 1098-4402. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- During the preparatory work for the optical-replica synthesizer experiment in the free-electron laser FLASH at DESY, we were able to superimpose a short, approximately 200 fs long pulse from a frequencydoubled mode-locked erbium laser with titanium-sapphire amplifier and an approximately 20 ps long electron bunch in an undulator. This induces an energy modulation in a longitudinal slice of the electron bunch. A magnetic chicane downstream of the undulator converts the energy modulation into a density modulation within the slice that causes the emission of coherent optical transition radiation from a silver-coated silicon screen. Varying the relative timing between electron and laser, we use a camera to record two-dimensional images of the slices as a function of the longitudinal position within the electron bunch.
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| 49. |
- Avery, P. J., et al.
(författare)
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A Proposal for an Individualized Pharmacogenetics-Based Warfarin Initiation Dose Regimen for Patients Commencing Anticoagulation Therapy
- 2011
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Ingår i: Clinical Pharmacology and Therapeutics. - : Springer Science and Business Media LLC. - 0009-9236 .- 1532-6535. ; 90:5, s. 701-706
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Tidskriftsartikel (refereegranskat)abstract
- A significant proportion of the interindividual variability in warfarin dose requirements can be explained on the basis of CYP2C9 and VKORC1 genotypes. We report the development of a novel pharmacogenetics-based 3-day warfarin initiation dose (ID) algorithm based on the International Warfarin Pharmacogenetics Consortium (IWPC) maintenance dose algorithm and the CYP2C9 genotype-based variance in warfarin half-life. The predictive value of the pharmacogenetics-based ID was assessed in a large cohort of 671 newly diagnosed patients with thromboembolic disorders who were about to commence anticoagulation therapy in accordance with standard induction regimens. In patients with mean international normalized ratio (INR)(days 4-7)>4.0 (n = 63) after warfarin initiation, the pharmacogenetics-based ID algorithm predicted a markedly lower dose requirement (median reduction = 4.2 mg), whereas in those with mean INR(days 4-7) < 2.0 (n = 145), the predicted dose requirement was very similar to that in the standard regimen. The use of a pharmacogenetics-based ID may avoid overshooting of INR in warfarin-sensitive patients without unduly affecting the time taken to reach target range in the majority of patients.
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| 50. |
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