Fragmentation branching ratios of highly excited hydrocarbon molecules CnH and their cations CnH+ (n<4)

We have measured fragmentation branching ratios of neutral CnH and CnH+ cations produced in high velocity (4.5 a.u) collisions between incident CnH+ cations and helium atoms. Electron capture gives rise to excited neutral species CnH and electronic excitation to excited cations CnH+. Thanks to a dedicated set-up, based on coincident detection of all fragments, the dissociation of the neutral and cationic parents were recorded separately and in a complete way. For the fragmentation of CnH, the H-loss channel is found to be dominant, as already observed by other authors. By contrast, the H-loss and C-loss channels equally dominate the two-fragment break up of CnH+ species. For these cations, we provide the first fragmentation data (n > 2). Results are also discussed in the context of astrochemistry

Assembly of small molecule surfactants at highly dynamic air-water interfaces

Small-angle neutron scattering has been used to probe the interfacial structure of foams stabilised by small molecule surfactants at concentrations well below their critical micelle concentration. The data for wet foams showed a pronounced Q−4 dependence at low Q and noticeable inflexions over the mid Q range. These features were found to be dependent on the surfactant structure (mainly the alkyl chain length) with various inflexions across the measured Q range as a function of the chain length but independent of factors such as concentration and foam age/height. By contrast, foam stability (for C < CMC) was significantly different at this experimental range. Drained foams showed different yet equally characteristic features, including additional peaks attributed to the formation of classical micellar structures. Together, these features suggest the dynamic air–water interface is not as simple as often depicted, indeed the data have been successfully described by a model consisting paracrystalline stacks (multilayer) of adsorbed surfactant layers; a structure that we believe is induced by the dynamic nature of the air–water interface in a foam

Investigation of Chernobyl 4-th unit materials by gamma activation method

Isotope and element content the samples of Chornobyl 4-th wrecking unit materials (concrete fragments and lava-like materials) were investigated by γ-activation method using bremsstrahlung of the electron accelerator. The concentration of a number of nuclides (U-238, Cs-137, Sr-90, Ni-58, Zr-90 etc.) and their depth distribution into concrete were determined as well as the corresponding correlation ratio. The comparison of the obtained data with the structure-phase analysis results was carried out

Potential neoplastic evolution of Vero cells: in vivo and in vitro characterization

Vero cell lines are extensively employed in viral vaccine manufacturing. Similarly to all established cells, mutations can occur during Vero cells in vitro amplification which can result in adverse features compromising their biological safety. To evaluate the potential neoplastic evolution of these cells, in vitro transformation test, gene expression analysis and karyotyping were compared among low- (127 and 139 passages) and high-passage (passage 194) cell lines, as well as transformed colonies (TCs). In vivo tumorigenicity was also tested to confirm preliminary in vitro data obtained for low passage lines and TCs. Moreover, Vero cells cultivated in foetal bovine serum-free medium and derived from TCs were analysed to investigate the influence of cultivation methods on tumorigenic evolution. Low-passage Vero developed TCs in soft agar, without showing any tumorigenic evolution when inoculated in the animal model. Karyotyping showed a hypo-diploid modal chromosome number and rearrangements with no difference among Vero cell line passages and TCs. These abnormalities were reported also in serum-free cultivated Vero. Gene expression revealed that high-passage Vero cells had several under-expressedand a few over-expressed genes compared to low-passage ones.Gene ontology revealed no significant enrichment of pathways related to oncogenic risk. These findings suggest that in vitro high passage, and not culture conditions, induces Vero transformation correlated to karyotype and gene expression alterations. These data, together with previous investigations reporting tumour induction in high-passage Vero cells, suggest the use of low-passage Vero cells or cell lines other than Vero to increase the safety of vaccine manufacturing