Resonant soft X-ray Raman scattering of NiO

Resonant soft X-ray Raman scattering measurements on NiO have been made at photon energies across the Ni 2p absorption edges. The details of the spectral features are identified as Raman scattering due to d-d and charge-transfer excitations. The spectra are interpreted within the single impurity Anderson model, including multiplets, crystal-field and charge-transfer effects. At threshold excitation, the spectral features consists of triplet-triplet and triplet-singlet transitions of the 3d8 configuration. For excitation energies corresponding to the charge-transfer region in the Ni 2p X-ray absorption spectrum of NiO, the emission spectra are instead dominated by charge-transfer transitions to the 3d9L-1 final state. Comparisons of the final states with other spectroscopical techniques are also made.Comment: 9 pages, 2 figures, 2 tables, http://iopscience.iop.org/0953-8984/14/13/32

Volatiles from Maruca vitrata (Lepidoptera, Crambidae) host plants influence olfactory responses of the parasitoid Therophilus javanus (Hymenoptera, Braconidae, Agathidinae)

Plants damaged by herbivores are known to release odors attracting parasitoids. However, there is currently no information how leguminous plants damaged by the pod borer Maruca vitrata attract the exotic larval parasitoid Therophilus javanus, which was imported into Benin from the putative area of origin of the pod borer in tropical Asia for assessing its potential as a biological control agent. In this study, we used Y-tube olfactometer bioassays to investigate T. javanus response towards odors emitted by four M. vitrata-damaged host plants: cowpea Vigna unguiculata, the most important cultivated host, and the naturally occurring legumes Lonchocarpus sericeus, Sesbania rostrata and Tephrosia platycarpa. Olfactory attraction of T. javanus was influenced by the species of plant damaged by the pod borer. Moreover, odors released from M. vitrata-infested host plant organs (flowers and pods) were discriminated over non-infested organs in cowpea and T. platycarpa, respectively. These results are discussed in the context of the possible impact of M. vitrata host plants on T. javanus foraging activity and subsequent establishment in natural environments following experimental releases

The electronic structure of poly(pyridine-2,5-diyl) investigated by soft x-ray absorption and emission spectroscopies

The electronic structure of the poly-pyridine conjugated polymer has been investigated by resonant and nonresonant inelastic X-ray scattering and X-ray absorption spectroscopies using synchrotron radiation. The measurements were made for both the carbon and nitrogen contents of the polymer. The analysis of the spectra has been carried out in comparison with molecular orbital calculations taking the repeat-unit cell as a model molecule of the polymer chain. The simulations indicate no significant differences in the absorption and in the non-resonant X-ray scattering spectra for the different isomeric geometries, while some isomeric dependence of the resonant spectra is predicted. The resonant emission spectra show depletion of the {\pi} electron bands in line with symmetry selection and momentum conservation rules. The effect is most vizual for the carbon spectra; the nitrogen spectra are dominated by lone pair n orbital emission of {\sigma} symmetry and are less frequency dependent.Comment: 11 pages, 7 figures, 1 table, http://www.sciencedirect.com/science/article/pii/S030101049800262

Genetic Background Strongly Modifies the Severity of Symptoms of Hirschsprung Disease, but Not Hearing Loss in Rats Carrying Ednrbsl Mutations

Hirschsprung disease (HSCR) is thought to result as a consequence of multiple gene interactions that modulate the ability of enteric neural crest cells to populate the developing gut. However, it remains unknown whether the single complete deletion of important HSCR-associated genes is sufficient to result in HSCR disease. In this study, we found that the null mutation of the Ednrb gene, thought indispensable for enteric neuron development, is insufficient to result in HSCR disease when bred onto a different genetic background in rats carrying Ednrbsl mutations. Moreover, we found that this mutation results in serious congenital sensorineural deafness, and these strains may be used as ideal models of Waardenburg Syndrome Type 4 (WS4). Furthermore, we evaluated how the same changed genetic background modifies three features of WS4 syndrome, aganglionosis, hearing loss, and pigment disorder in these congenic strains. We found that the same genetic background markedly changed the aganglionosis, but resulted in only slight changes to hearing loss and pigment disorder. This provided the important evidence, in support of previous studies, that different lineages of neural crest-derived cells migrating along with various pathways are regulated by different signal molecules. This study will help us to better understand complicated diseases such as HSCR and WS4 syndrome