| 81. |
- Piancastelli, M. N., et al.
(författare)
-
Bond-distance-dependent decay probability of the N 1s -> pi* core-excited state in N-2
- 2000
-
Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 33:9, s. 1819-1826
-
Tidskriftsartikel (refereegranskat)abstract
- We report the observation of the unusually weak decay of the N 1s --> pi* core-excited N-2 molecule to the (B) over tilde (2)Sigma(u)(+) final state of N-2(+), which is only detectable in an experiment with high sensitivity. The resonant Auger spectra exhibit an unexpected dependence on the selected vibrational level of the intermediate state. Theoretical calculations show that the interference between direct and resonant photoemission as well as a strong geometry dependence of the decay probability on the bond distance give rise to the observed features.
|
|
| 82. |
- Rosenqvist, L., et al.
(författare)
-
Femtosecond dissociation of ozone studied by the Auger Doppler effect
- 2001
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 115:8, s. 3614-3620
-
Tidskriftsartikel (refereegranskat)abstract
- The peaks arising from the decay of the excited oxygen atom were studied. Fast dissociation of core-excited ozone was confirmed by the presence of Auger emission from atomic oxygen in the decay spectrum from the ozone OT 1s-σ*(7a1) state. No such emission was observed after excitation of the corresponding state on the central oxygen atom. An angle-dependent energy shift of the atomic lines was observed. Analysis of the energy shift revealed that the kinetic energy released in the dissociation process is approximately 3.3 ± 0.3eV. An energy release of 8.45 was found by application of a Born-Haber cycle.
|
|
| 83. |
- Ryding, Mauritz Johan, 1981, et al.
(författare)
-
X-ray induced fragmentation of size-selected salt cluster-ions stored in an ion trap
- 2014
-
Ingår i: RSC Advances. - 2046-2069. ; 4:88, s. 47743-47751
-
Tidskriftsartikel (refereegranskat)abstract
- A method for spectroscopic characterization of free ionic clusters and nanoparticles utilizing X-ray synchrotron radiation is presented. We demonstrate that size-selected ammonium bisulphate cluster ions, NH 4+(NH 4HSO4) n, captured in a linear ion trap, exhibit well-defined core-level absorption edges in the reconstructed fragment-ion abundance spectra. In addition to the specific photo-fragmentation pathways observed at the N1s-, O1s- and S2p-edges, dissociation also occurs as a consequence of clusters colliding with helium present as buffer gas in the ion trap. Separate off-beam experiments were conducted to establish the activation kinetics of these collision induced dissociation processes. Furthermore, it is demonstrated that the electrons released upon photoionization of background helium are too few in number to produce multiply charged cluster ions, and thereby induce fragmentation of the salt clusters, to any significant degree. The mechanisms for photon absorption and subsequent cluster fragmentation are analysed and discussed. In addition to its inherent element specificity, the method holds promise for cluster structure elucidation resulting from the sensitivity of the near edge absorption structure to the local chemical environment of the excited atom.
|
|
| 84. |
- Salek, Pawel, et al.
(författare)
-
Resonant x-ray Raman scattering involving avoided crossings in the final-state potential-energy curves
- 2000
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : Elsevier BV. - 1050-2947 .- 1094-1622. ; 62:6
-
Tidskriftsartikel (refereegranskat)abstract
- The role of avoided crossings for resonant x-ray Raman scattering is explored. The strong dependence of the electronic transition amplitudes on internuclear distance at avoided crossings causes new, and even anomalous, spectral features, and can bring about a breakdown of the generally accepted participator or spectator classification of the transitions. We report, and apply the theory on, an experimental observation of the electron decay of the N 1s-->pi* core-excited level in N-2 the B(2)Sigma (+)(u) final state with peculiar, non-Franck-Condon, vibrational intensity distributions.
|
|
| 85. |
- Sałek, P., et al.
(författare)
-
Resonant X-ray Raman scattering involving avoided crossings in the final-state potential-energy curves
- 2000
-
Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 1050-2947. ; 62:6, s. 62501-62506
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of avoided crossings on the spectral profiles of resonant X-ray Raman scattering was investigated. The theory was also applied to nitrogen molecule in the core-excited level to analyze the electron decay process. The dependence of internuclear distance on electron transition amplitude was considered important with respect to the breakdown process of the transition. The correlation between the nuclear and electronic degrees of freedom was also reported.
|
|
| 86. |
|
|
| 87. |
- Stevens, Kristen N., et al.
(författare)
-
Common Breast Cancer Susceptibility Loci Are Associated with Triple-Negative Breast Cancer
- 2011
-
Ingår i: Cancer Research. - 1538-7445. ; 71:19, s. 6240-6249
-
Tidskriftsartikel (refereegranskat)abstract
- Triple-negative breast cancers are an aggressive subtype of breast cancer with poor survival, but there remains little known about the etiologic factors that promote its initiation and development. Commonly inherited breast cancer risk factors identified through genome-wide association studies display heterogeneity of effect among breast cancer subtypes as defined by the status of estrogen and progesterone receptors. In the Triple Negative Breast Cancer Consortium (TNBCC), 22 common breast cancer susceptibility variants were investigated in 2,980 Caucasian women with triple-negative breast cancer and 4,978 healthy controls. We identified six single-nucleotide polymorphisms, including rs2046210 (ESR1), rs12662670 (ESR1), rs3803662 (TOX3), rs999737 (RAD51L1), rs8170 (19p13.1), and rs8100241 (19p13.1), significantly associated with the risk of triple-negative breast cancer. Together, our results provide convincing evidence of genetic susceptibility for triple-negative breast cancer. Cancer Res; 71(19); 6240-9. (C)2011 AACR.
|
|
| 88. |
- Van Odijk, Jenny, 1969, et al.
(författare)
-
The Use of DAO as a Marker for Histamine Intolerance: Measurements and Determinants in a Large Random Population-Based Survey
- 2023
-
Ingår i: Nutrients. - 2072-6643. ; 15:13
-
Tidskriftsartikel (refereegranskat)abstract
- Histamine intolerance (HIT) is a common adverse reaction to food where elimination and reintroduction of histamine-rich food is part of the investigation. Analysis of the enzyme diamine oxidase (DAO) is sometimes used as an additional tool for diagnosis. This study aimed to describe the distribution of DAO in a large representative cohort of adults and to determine the association between DAO activity and possible associated factors. The study is based on the population-based West Sweden Asthma Study and includes 1051 subjects. Subjects underwent structured interviews including questions on demography, asthma, allergy symptoms, and lifestyle factors. Subjects were assessed for specific-IgE-antibodies and measurement of DAO activity in serum. Previously suggested cut-off levels for low values (<3 U/mL), normal values (>10 U/mL), and median levels of DAO were used. In the group of 1051 subjects, only a few presented reactions upon histamine intake, whereas 44% presented DAO levels below the suggested normal cut-off levels. BMI and age were shown to have an impact on DAO activity among women with increasing activity of DAO with increasing BMI and age. Among men, only increasing age was seen to have an impact on DAO levels. There was no difference in DAO levels with different sensitization status to common foods or airborne allergens. No association between DAO levels and reported symptoms to histamine-rich foods could be found. In conclusion, the determination of the DAO enzyme needs to be re-evaluated and may not be used as a valuable tool for histamine intolerance using current cut-off values. Further studies are needed to improve the use of DAO as a biomarker for histamine intolerance.
|
|
| 89. |
- Van Steenwinckel, Juliette, et al.
(författare)
-
Decreased microglial Wnt/β-catenin signalling drives microglial pro-inflammatory activation in the developing brain.
- 2019
-
Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 142:12, s. 3806-3833
-
Tidskriftsartikel (refereegranskat)abstract
- Microglia of the developing brain have unique functional properties but how their activation states are regulated is poorly understood. Inflammatory activation of microglia in the still-developing brain of preterm-born infants is associated with permanent neurological sequelae in 9 million infants every year. Investigating the regulators of microglial activation in the developing brain across models of neuroinflammation-mediated injury (mouse, zebrafish) and primary human and mouse microglia we found using analysis of genes and proteins that a reduction in Wnt/β-catenin signalling is necessary and sufficient to drive a microglial phenotype causing hypomyelination. We validated in a cohort of preterm-born infants that genomic variation in the Wnt pathway is associated with the levels of connectivity found in their brains. Using a Wnt agonist delivered by a blood-brain barrier penetrant microglia-specific targeting nanocarrier we prevented in our animal model the pro-inflammatory microglial activation, white matter injury and behavioural deficits. Collectively, these data validate that the Wnt pathway regulates microglial activation, is critical in the evolution of an important form of human brain injury and is a viable therapeutic target.
|
|
| 90. |
- Wang, H., et al.
(författare)
-
Filtering core excitation spectra : Vibrationally resolved constant ionic state studies of N 1s → 2π core-excited NO
- 2001
-
Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 34:22, s. 4417-4426
-
Tidskriftsartikel (refereegranskat)abstract
- High-resolution electron spectroscopy studies of the NO molecule in the regions of the N 1s → 2π core excitations have been performed. By selecting electrons within certain binding energy ranges, either the Auger electron yield - a good approximation for the x-ray absorption spectrum - or the electrons emitted after decay to a particular ionic final state (constant ionic state (CIS)) were detected. By selecting the X 1Σ+ (2π0) final state, the superposition of several intermediate state can be disentangled by exploiting a selection rule which permits only two of the three dipole-allowed intermediate states to decay to this specific final state. This makes it possible to obtain more detailed information on the potential energy curves of the intermediate states than is available from regular absorption measurements. We have also obtained CIS spectra for individual vibrational sublevels within this state. The role of lifetime vibrational interference on the appearance of these spectra is discussed.
|
|
