Nucleation of Ga droplets on Si and SiOx surfaces.

We report on gallium droplet nucleation on silicon (100) substrates with and without the presence of the native oxide. The gallium deposition is carried out under ultra-high vacuum conditions at temperatures between 580 and 630 °C. The total droplet volume, obtained from a fit to the diameter-density relation, is used for sample analysis on clean silicon surfaces. Through a variation of the 2D equivalent Ga thickness, the droplet diameter was found to be between 250-1000 nm. Longer annealing times resulted in a decrease of the total droplet volume. Substrate temperatures of 630 °C and above led to Ga etching into the Si substrates and caused Si precipitation around the droplets. In contrast, we obtained an almost constant diameter distribution around 75 nm over a density range of more than two orders of magnitude in the presence of a native oxide layer. Furthermore, the droplet nucleation was found to correlate with the density of surface features on the 'epi-ready' wafer.

The I.F.A.S.T. model allows the prediction of conversion to Alzheimer disease in patients with mild cognitive impairment with high degree of accuracy.

This paper presents the results obtained with the innovative use of special types of artificial neural networks (ANNs) assembled in a novel methodology named IFAST (implicit function as squashing time) capable of compressing the temporal sequence of electroencephalographic (EEG) data into spatial invariants. The aim of this study is to test the potential of this parallel and nonlinear EEG analysis technique in providing an automatic classification of mild cognitive impairment (MCI) subjects who will convert to Alzheimer's disease (AD) with a high degree of accuracy. Eyes-closed resting EEG data (10-20 electrode montage) were recorded in 143 amnesic MCI subjects. Based on 1-year follow up, the subjects were retrospectively classified to MCI converted to AD and MCI stable. The EEG tracks were successively filtered according to four different frequency ranges, in order to evaluate the hypotheses that a specific range, corresponding to specific brain wave type, could provide a better classification (0.12 Hz, 12.2 - 29.8 Hz; 30.2 - 40 Hz, and finally Notch Filter 48 - 50 Hz). The spatial content of the EEG voltage was extracted by IFAST step-wise procedure using ANNs. The data input for the classification operated by ANNs were not the EEG data, but the connections weights of a nonlinear auto-associative ANN trained to reproduce the recorded EEG tracks. These weights represented a good model of the peculiar spatial features of the EEG patterns at scalp surface. The classification based on these parameters was binary and performed by a supervised ANN. The best results distinguishing between MCI stable and MCI/AD reached to 85.98%.(012 Hz band). And confirmed the working hypothesis that a correct automatic classification can be obtained extracting spatial information content of the resting EEG voltage by ANNs and represent the basis for research aimed at integrating spatial and temporal information content of the EEG. These results suggest that this low-cost procedure can reliably distinguish eyes-closed resting EEG data in individual MCI subjects who will have different prognosis at 1-year follow up, and is promising for a large-scale periodic screening of large populations at amnesic MCI subjects at risk of AD.

Duchenne muscular dystrophy. Morphological study of erythrocytes after treatment with L-alpha-lysophosphatidyl-choline in dystrophic patients and in the carrier state.

The percentage of echinocytes in the blood from patients affected by Duchenne muscular dystrophy, in mothers carriers of the dystrophic state, and in Steinert dystrophic patients, has been investigated after addition of low levels of lysolecithin. The echinocyte content was significantly higher in both Duchenne patients and in carriers, and lower in Steinert patients than in controls. The extents of the differences suggest the possibility to use this methodology as a diagnostic test in Duchenne muscular dystrophy.

Fluidity of erythrocyte membranes from patients with Duchenne muscular dystrophy: studies in intact erythrocytes and in ghosts.

We have studied the alterations of fluidity in intact erythrocytes and in erythrocyte membranes from patients with Duchenne muscular dystrophy. The interest of this study was to comparison directly two types of results; these demonstrate an increase of fluidity in the erythrocytic membranes, no changes are present when the label is incorporated in intact erythrocytes. It might be inferred that hypotonic haemolysis removes components that are more weakly bound in Duchenne membranes, and that exert an immobilizing effect on the membrane lipids.

Biophysical studies of erythrocyte membranes from patients with duchenne muscular dystrophy.

Lipid-soluble spin labels were used to probe the fluidity of membrane lipids in erythrocyte membranes from patients with Duchenne muscular dystrophy. A greater mobility of spin label motion was noticed at the surface of the Duchenne erythrocyte membranes in comparison with the similary labeled normal human erythrocytes. Changes in the protein conformation and/or protein-lipid organization, as a consequence of an altered membrane lipid fluidity, have been demonstrated by the use of a sulfhydryl group specific protein spin label. Strongly immobilized sulfhydryl groups appear to be located both at the membrane surface and deep within the lipid bilayer. The ratio of the spectral amplitude of the spin label attached to weakly immobilized sulfhydryl groups to that of strongly immobilized SH-groups is significantly greater in Duchenne membranes, compared to those of controls. These studies suggest alterations in lipid-protein organization at the surface of Duchenne erythrocytes, indicating that Duchenne muscular dystrophy may be a disease resulting from a membrane abnormality at the molecular level.

[Interaction of the genes of progressive muscular dystrophy (PMD) and blood groups (ABO)]. / Interazione tra i geni delle distrofie muscolari progressive (D.M.P.) e dei gruppi sanguigni (ABO).

Verification of the hypothesis that the inheritance of the Progressive Muscular Dystrophies (PMD) may involve dispersed genes, throiugh the study of a sample of 105 patients revealed that 82% of the Duchenne type belong to blood group O, while 79% of the limb-girdle type belong to group A. The fact that the Duchenne gene is sex-linked while the ABO locus is on chromosome 9 confirms the "dispersed genes" hypothesis, with important implications for further research, for genetic counselin and possibly for prevention.

Progressive muscular dystrophy type Duchenne. I. Spin label studies on the physico-chemical state of erythrocyte membranes.

Electron spin resonance studies of erythrocyte membranes from patients with Duchenne muscular dystrophy exhibit changes in the physical state of lipids and proteins in membranes when compared to membranes from normal subjects. The results suggest that the alterations in membrane lipid-protein organization are present in this disease.

Progressive muscular dystrophy type Duchenne. II. Viscosity and resistence to erythrolytic compounds of erythrocyte membranes.

The transition temperature of erythrocyte ghosts of normal subjects is about 18-20 degrees C. We have studied the viscosity of erythrocyte ghosts of dystrophic children, showing that the transition shifts to lower temperatures (17-18 degrees C). After treatment with erythrocytic compounds like L-Lyso phosphatidyl-Choline dystrophic erythrocytes hemolize at lower Lysophosphatidyl-Choline concentration and at a greater extents than these of normal and carriers subjects.