UV-induced dissociation of CH2BrI probed by intense femtosecond XUV pulses

The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH2BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump — XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH2Br radicals produced by C—I bond cleavage is investigated. In earlier charge-transfer studies, the center of mass of the molecules was located along the axis of the bond cleaved by the pump pulse. In the present case of CH2BrI, this is not the case, thus inducing a rotation of the fragment. We discuss the influence of the rotation on the charge transfer process using a classical over-the-barrier model. Our modeling suggests that, despite the fact that the dissociation is slower due to the rotational excitation, the critical interatomic distance for charge transfer is reached faster. Furthermore, we suggest that charge transfer during molecular fragmentation may be modulated in a complex way.

Determinations of fission cross-sections and fission yields from proton induced fission reactions of 232Th, 233,235,236,238U, 237Np and 239Pu

In this work, the proton induced fission reaction cross-sections and fission yields are calculated for some actinides [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] using the fission barrier models of the TALYS 1.95 code. Cross-sections and fission yield calculations are carried out up to 100 MeV incident proton energies. The calculation results are compared with the available experimental data in the EXFOR library. In addition, a relative variance analysis of fission barrier models was done to determine the fission barrier model whose results best matched with the experimental results. Among the fission barrier models, the best agreement with the experimental data is obtained from the rotating-finite-range fission barrier model calculation for the [Formula: see text] reaction of the studied nuclei having the atomic mass number larger than 230. On the other hand, fission barrier heights for the studied reactions are determined using the same models.

Pericytes of Indirect Contact Coculture Decrease Integrity of Inner Blood-Retina Barrier Model In Vitro by Upgrading MMP-2/9 Activity

Inner blood-retina barrier (iBRB) is primarily formed of retinal microvascular endothelial cells (ECs) with tight junctions, which are surrounded and supported by retinal microvascular pericytes (RMPs) and basement membrane. Pericytes are believed to be critically involved in the physiology and pathology of iBRB. However, the underlying mechanism remains to be fully elucidated. We developed a novel in vitro iBRB model which was composed of primary cultures of rat retinal ECs and RMPs based on Transwell system. We tested the involvement of pericytes in the migration and invasion of ECs, examined the expression and activity of matrix metalloproteinase- (MMP-) 2/MMP-9 in the culture, evaluated the TEER and permeability of iBRB, and assessed the expression of ZO-1, occludin, claudin-5, and VE-cadherin of endothelial junctions. We found that RMPs with indirect contact of ECs can increase the expression of MMP-2 and upgrade the activity of MMP-2/9 in the coculture, which subsequently decreased TJ protein abundance of ZO-1 and occludin in ECs, promoted the migration of ECs, and finally reduced the integrity of iBRB. Taken together, our data show that RMP relative location with ECs is involved in the integrity of iBRB via MMP-2/9 and has important implications for treating diabetic retinopathy and other retinal disorders involving iBRB dysfunction.