We investigate the photodouble ionization of H_{2} molecules with 400 eV photons. We find that the emitted electrons do not show any sign of two-center interference fringes in their angular emission ...distributions if considered separately. In contrast, the quasiparticle consisting of both electrons (i.e., the "dielectron") does. The work highlights the fact that nonlocal effects are embedded everywhere in nature where many-particle processes are involved.
The original version of this Article contained an error in the fifth sentence of the first paragraph of the 'Application on H
' section of the Results, which incorrectly read 'The role of electron ...correlation is quite apparent in this presentation: Fig. 1a is empty for the uncorrelated Hartree-Fock wave function, since projection of the latter wave function onto the 2pσ
orbital is exactly zero, while this is not the case for the fully correlated wave function (Fig. 1d); also, Fig. 1b, c for the uncorrelated description are identical, while Fig. 1e, f for the correlated case are significantly different.' The correct version replaces 'Fig. 1e, f' with 'Fig. 2e and f'.
The time-dependent multiphoton ionization of xenon atoms is studied with femtosecond pulses in the excitation range of the 4d giant resonance at the photon energy of 93 eV. Benefiting from a new ...operation mode of the free electron laser FLASH, the measurements are performed with varying pulse durations. A strong dependence of the ion charge distribution on the pulse duration allows the different multiphoton mechanisms behind the multiple photoionization of xenon to be disentangled up to a charge state of Xe super(10+). The results up to Xe super(8+) are well explained by sequences of single photon, multiphoton, and Auger processes, but higher charge state generation suggests the need for collective electron multiphoton excitations.
The fragmentation pattern of the iodine-containing molecules
and
following a strong multiphoton excitation in the vicinity of the iodine 4d giant resonance regime is studied using soft X-ray free ...electron laser radiation. A strong difference of the charge distribution and the kinetic energy release (KER) for the two molecules is found. The effects can be attributed to charge rearrangement processes induced by the photoexcitation. The difference in the observed distribution for higher charge states of iodine and carbon fragments is consistent with an over-the-barrier model for the charge rearrangement in the dissociating molecules. The KER for singly ionised carbon fragments indicates an ultrafast charge rearrangement before the dissociation starts.
Our previous studies indicate that reduction of lipocalin 2 (mouse 24p3) expression by either anti-sense or siRNA approaches strongly reduces the overgrowth of BCR-ABL+ mouse myeloid 32D in marrow ...and spleen of NOD/SCID mice. In this study, we used the mouse bone marrow transplant model to further explore the role of 24p3 in BCR-ABL-induced leukemia. Consistent with our previous findings, when using non-irradiated mice as recipient, donor marrow cells expressing BCR-ABL but lacking 24p3 did not cause leukemia or any disease after 75 days, whereas all mice receiving wild type BCR-ABL donor cells died with CML-like disease. An agar clone of the BCR-ABL+ human CML cell line K562 (C5) that secretes relatively high levels of lipocalin 2 (human NGAL) induced suppression of hematopoiesis in spleen and marrow of mice, leading to early death in contrast to parental K562 or K562 clone (C6) expressing low amounts of NGAL. Compared with K562 cells, overexpressing NGAL in K562 led to a higher apoptosis rate and an atrophy phenotype in the spleen of the inoculated mice. Plasma from both leukemic mice and CML patients showed elevated lipocalin 2 levels compared with healthy individuals. Moreover, we found that a primary stable cell line from wild-type mouse marrow cells expressing BCR-ABL caused solid tumors in nude mice whereas a similar BCR-ABL+ cell line from 24p3 null mice did not. These findings demonstrate that lipocalin 2 has at least two functions related to tumorigenesis, one involving apoptosis induction of normal hematopoietic cells and the other being tissue invasion by leukemia cells.
SSBP proteins bind and stabilize transcriptional cofactor LIM domain-binding protein1 (LDB1) from proteosomal degradation to promote tissue-specific transcription through an evolutionarily conserved ...pathway. The human SSBP2 gene was isolated as a candidate tumor suppressor from a critical region of loss in chromosome 5q14.1. By gene targeting, we show increased predisposition to B-cell lymphomas and carcinomas in Ssbp2(-/-) mice. Remarkably, loss of Ssbp2 causes increased LDB1 turnover in the thymus, a pathway exploited in Trp53(-/-)Ssbp2(-/-) mice to develop highly aggressive, immature thymic lymphomas. Using T-cell differentiation as a model, we report a stage-specific upregulation of Ssbp2 expression, which in turn regulates LDB1 turnover under physiological conditions. Furthermore, transcript levels of pTalpha, a target of LDB1-containing complex, and a critical regulator T-cell differentiation are reduced in Ssbp2(-/-) immature thymocytes. Our findings suggest that disruption of the SSBP2-regulated pathways may be an infrequent but critical step in malignant transformation of multiple tissues.
Synopsis Photoprocesses of the endohedral fullerene ions Sc3N@C80+ and Sc3N@C80− in the gas phase have been experimentally investigated with emphasis on the specific effects of the encapsulated ...trimetallic nitride cluster Sc3N on the observed reaction yields. Clear evidence of photoexcitation near the Sc L edge is obtained with the dominating contributions visible in the one- and two-electron-removal channels. The experiments are accompanied by model calculations employing density functional theory (DFT).
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