Photofragmentation of the protonated water dimer H+(H2O)_{2}, a fundamental system both in aqueous solutions and gas-phase water clusters, has been studied at 13.8 nm using the Free Electron Laser ...FLASH in Hamburg. In a crossed-beam experiment using time-resolved, single-molecule fragment imaging, the two-body breakup into H2O++H3O+ was found as a prominent fragmentation channel with a kinetic energy release of up to 10 eV. This channel was observed with at least a similar yield as events with stronger fragmentation, producing protons together with neutral fragments and showing an absolute cross section of (0.5 ± 0.2) × 10(-18) cm2.
The transport of cargo particles that are pulled by several molecular motors in a cooperative manner is studied theoretically in this article. The transport properties depend primarily on the maximal ...number N of motor molecules that may pull simultaneously on the cargo particle. Because each motor must unbind from the filament after a finite number of steps but can also rebind to it again, the actual number of pulling motors is not constant but varies with time between zero and N. An increase in the maximal number N leads to a strong increase of the average walking distance (or run length) of the cargo particle. If the cargo is pulled by up to N kinesin motors, for example, the walking distance is estimated to be$5^{N-1}/N$micrometers, which implies that seven or eight kinesin molecules are sufficient to attain an average walking distance in the centimeter range. If the cargo particle is pulled against an external load force, this force is shared between the motors, which provides a nontrivial motor-motor coupling and a generic mechanism for nonlinear force-velocity relationships. With increasing load force, the probability distribution of the instantaneous velocity is shifted toward smaller values, becomes broader, and develops several peaks. Our theory is consistent with available experimental data and makes quantitative predictions that are accessible to systematic in vitro experiments.
Aprosencephaly is a rare condition in veterinary and human medicine characterized by the complete absence of telencephalon and diencephalon. Some cases are accompanied by a facial dysmorphism ...designated as otocephaly. A stillborn lamb had splanchnocranial anomalies that were classified by computed tomography, magnetic resonance imaging, and pathologic examination as aprosencephaly and otocephaly. The brain included parts of the cerebellum and brainstem but no telencephalon, diencephalon, or mesencephalon. The cerebellum had a structurally normal cortex with expression of neuronal nuclear antigen in the inner and doublecortin in the outer granular cell layers, as well as an irregularly situated nucleus dentatus. Aprosencephaly with otocephaly has been described in mice with heterozygous mutations in the Otx2 gene; however, no causative polymorphisms were detected in the Otx2 gene region of this lamb.
Synopsis Absolute cross sections for triple photoionization of C+ ions have been measured. Direct triple-Auger decay of K-shell excited states, i.e., an interaction process involving four electrons ...that results in the simultaneous emission of three electrons, could be unambiguously observed and quantified.
Synopsis Photoionization of Xe3+, Xe4+ and Xe5+ ions was measured in the energy range 670-750 eV, including the 3d ionization threshold. The cross sections exhibit a progressively larger number of ...sharp resonances as the ion charge state is increased. This clearly visualizes the re-ordering of the f continuum into a regular series of (bound) Rydberg orbitals as the ionic core becomes more attractive.
Activity of serine/threonine protein phosphatase type 2C is known to be stimulated by certain unsaturated fatty acids and this enzyme dephosphorylates Bad, thus acting on apoptosis. This prompted us ...to investigate endothelial cell death. Here, we present evidence for the presence of protein phosphatase type 2Cβ (PP2Cβ) in human umbilical vein endothelial cells (HUVECs) and report on colocalization of PP2Cβ and Bad in the cytosol of endothelial cells. Lipophilic compounds that stimulated PP2Cβ activity in vitro were found to induce cell death of HUVECs. Lipoproteins did neither influence PP2Cβ activity nor affect cell behaviour. Lipoproteins treated with the lipoprotein lipase, however, stimulated the activity of PP2Cβ at least 10-fold concomitantly triggering cell death. Analytical methods revealed that both effects – stimulation of PP2Cβ and apoptosis – were caused by free fatty acids liberated from VLDL, LDL and HDL with oleic acid and linoleic acid as major constituents.
The results provide novel insights in endothelial apoptosis and suggest that PP2Cβ participates in the development and progress of atherosclerosis.
Background Ovarian pathology is an important cause of decreased fertility and reproductive capability and may impact multiple systems, particularly in aging rhesus macaques.
Methods Retrospective ...histopathologic and immunohistochemical analysis of 458 female rhesus macaque necropsies over 12 years at the New England Primate Research Center in Southborough, MA.
Results Degenerative and inflammatory changes in the ovaries included mineralization, infiltration by lymphocytes, macrophages and multinucleated giant cells, endometriosis, and arteriopathy. Cystic changes included follicular cysts, cystic rete, and mesonephric duct cysts with cystic rete the most common. Neoplasms included granulosa cell tumors, cystadenoma, cystadenocarcinoma, and teratoma.
Conclusions Ovarian lesions of the rhesus macaque are similar to those of cynomolgus macaques and humans. These lesions are frequently incidental findings but may impact metabolic and neurocognitive studies.
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