Impact of kinetics on the growth of GaN on graphene by plasma-assisted molecular beam epitaxy.

The growth of GaN on graphene by molecular beam epitaxy was investigated. The most stable epitaxial relationship, i.e. [00.1]-oriented grains, is obtained at high temperature and N-rich conditions, which match those for nanowire growth. Alternatively, at moderate temperature and Ga-rich conditions, several metastable orientations are observed at the nucleation stage, which evolve preferentially towards [00.1]-oriented grains. The dependence of the nucleation regime on growth conditions was assigned to Ga adatom kinetics. This statement is consistent with the calculated graphene/GaN in-plane lattice coincidence and supported by a combination of transmission electron microscopy, x-ray diffraction, photoluminescence, and Raman spectroscopy experiments.

Environmental yeast communities in vineyards in the mountains of Santa Catarina State, Brazil.

Yeasts were isolated from three vineyards located in the South Region of Brazil. A cross evaluation was carried out at the oldest vineyard of the study in Pinheiro Preto. Samples of grape berries, grapevine leaves and the soil, along with samples of the winery equipment and effluent, were collected. In the Serra do Marari and Campos Novos vineyards only samples of grape clusters were obtained. The 106 yeast isolates were identified by sequencing the D1/D2 domain of LSU rDNA or ITS1-5.8S-ITS2 region in 22 species. The values for the richness indices varied between the vineyards. A comparison of the taxonomic diversity of the yeasts from these regions using the reciprocal Simpson index showed a significant difference between the Serra do Marari and Campos Novos vineyards (5.72 ± 0.36 and 2.92 ± 0.36, respectively, p < 0.0001). The functional diversity was assessed in relation to the use of carbon and nitrogen sources by the yeasts isolated from each location. In general, we observed that the Pinheiro Preto and Campos Novos vineyards differed consistently from the Serra do Marari vineyard according to these indices (FAD2, FDc and Rao, p < 0.0001). The possible spreading of Saccharomyces cerevisiae from the winery to the vineyard in Pinheiro Preto was observed.

T-lymphocyte subpopulations in acute unilateral optic neuritis.

The authors prospectively analyzed T-lymphocyte subpopulations in the peripheral blood of nine patients with acute unilateral optic neuritis and compared them with 25 controls without neurologic disease. The presence or absence of alterations in circulating T-cell subsets has not been examined previously in patients with isolated optic neuritis. The authors found the mean ratio of inducer (CD4) to suppressor (CD8) T-lymphocytes was 2.07 +/- 0.51 for the group with optic neuritis, statistically indistinguishable from a value of 1.78 +/- 1.04 for the control group. Multiple sclerosis (MS) subsequently developed in one patient. Her inducer/suppressor T-cell ratio was initially 2.66, but progressively increased to 3.68 concomitant with the clinical manifestation of focal neurologic signs. Although optic neuritis may be the initial clinical sign of MS, the periodic alteration of circulating T-lymphocytes increasing the inducer/suppressor T-cell ratio in MS was not observed in those with isolated optic neuritis.