Experimental study of the Bauschinger effect for anisotropic metals

The Bauschinger effect is characterized by the Bauschinger and Backhaus functions. The dependence of these functions on the direction of deformation of an initially anisotropic sheet material is studied. The experiments showed that these functions are independent of the direction, which confirms the model of isotropic Bauschinger effect.     

Comparison of direct photon production in pp collisions at s= 30.6 GeV and 53.2 GeV

We present data obtained at the ISR, on the determination of the ratio $\text{R =}\text{γ}\text{π}{}^0\text{at}\text{s}\text{= 30.6}$ GeV and we compare the results with our previous measurement at $\text{s}\text{= 53.2}$ GeV. The ratio $\text{R =}\text{γ}\text{π}{}^0$ integrated over the interval 0.1 ? χ_T ? 0.2 is (1.6 ± 0.5) × 10^?2 and we obtain an indication of a universal χ_T dependence.     

Putative palytoxin and its new analogue,ovatoxin-a,in <Emphasis Type="Italic">Ostreopsis ovata</Emphasis> collected along the ligurian coasts during the 2006 toxic outbreak

In this article we report on the liquid chromatography tandem mass spectrometry (LC-MS) investigation of plankton samples collected in the summer of 2006 along the Ligurian coasts, coinciding with a massive bloom of the tropical microalga Ostreopsis ovata. LC-MS analyses indicated the occurrence of putative palytoxin along with a much more abundant palytoxin-like compound never reported so far, which we named ovatoxin-a. On the basis of molecular formula, fragmentation pattern, and chromatographic behavior, the structure of ovatoxin-a appeared to be strictly related to that of palytoxin. We report also on the analysis of cultured O. ovata, which was necessary to unequivocally demonstrate that putative palytoxin and ovatoxin-a contained in field samples were actually produced by O. ovata itself.     

Order and disorder in titanosilicate glass by 17O MAS, off-MAS, and 3Q-QCPMG-MAS solid-state NMR

An 17O-enriched version of the titanosilicate glass, KTS2 (K(2)O.TiO(2).2SiO(2)), was analyzed by 17O MAS, off-MAS, and 3Q-QCPMG-MAS experiments. Exploiting the variations in EFG and CSA parameters for the 17O sites in KTS2 glass, we detected four types of oxygen by reduction of spinning sideband intensities in the off-MAS experiments. From the 17O off-MAS and 3Q-QCPMG-MAS experiments, the Si-O-Ti and K-O-Ti resonances were characterized by a distribution of isotropic chemical shifts, whereas the Si-O-Si resonance was characterized by very small distributions of both EFG tensor and isotropic chemical shift, which means that the disorder in the glass is closely related to Ti. In addition to the order/disorder issue, the most striking feature about the 17O off-MAS experiments on KTS2 is the lack of signals from Ti-O-Ti, which contradicts linking between corner sharing TiO(5) units. Therefore, the structure must consist of linkages between TiO(5) units and SiO(4) tetrahedra and linkages between SiO(4) tetrahedra.     

Disruption of urogenital biofilms by lactobacilli

The process that changes a relatively sparse vaginal microbiota of healthy women into a dense biofilm of pathogenic and potentially pathogenic bacteria is poorly understood. Likewise, the reverse step whereby an aberrant biofilm is displaced and returns to a healthy lactobacilli dominated microbiota is unclear. In order to study these phenomena, in vitro experiments were performed to examine the structure of biofilms associated with aerobic vaginosis, urinary tract infections, and bacterial vaginosis (BV). Uropathogenic Escherichia coli were able to form relatively thin biofilms within five days (6 μm height), while Atopobium vaginae and Gardnerella vaginalis formed thicker biofilms 12 μm in height within two days. Challenge of E. coli biofilms with lactobacilli did not result in pathogen displacement. However, the resulting thicker lactobacilli infused biofilms, caused significant E. coli killing. E. coli biofilms challenged with secreted products of L. rhamnosus GR-1 caused a marked decrease in cell density, and increased cell death. Similarly challenge of BV biofilms with lactobacilli infiltrated BV biofilms and caused bacterial cell death. Metronidazole produced holes in the biofilm but did not eradicate the organisms. The findings provide some evidence of how lactobacilli probiotics might interfere with an aberrant vaginal microbiota, and strengthen the position that combining probiotics with antimicrobials could better eradicate pathogenic biofilms.