Universality of liquid-gas Mott transitions at finite temperatures

We explain, in a consistent manner, the set of seemingly conflicting experiments on the finite temperature Mott critical point, and demonstrate that the Mott transition is in the Ising universality class. We show that, even though the thermodynamic behavior of the system near such critical point is described by an Ising order parameter, the global conductivity can depend on other singular observables and, in particular, on the energy density. Finally, we show that in the presence of weak disorder the dimensionality of the system has crucial effects on the size of the critical region that is probed experimentally.     

Green's function calculations of the hyperfine interaction for impurities in metals andfor metallic interfaces

We present local density functional calculations for magnetic impurities andmagnetic monolayers in non-magnetic metals. The calculations employ a multiple scattering (KKR) Green's function method for impurities in the bulk andfor ideal surfaces and interfaces. In particular we discuss the moment formation of 3d and4d impurities in alkali andnoble metals. Special emphasis is put on an accurate calculation of the host polarization around 3d impurities in Cu andPd. While the calculated impurity hyperfine fields in Cu contain rather large errors due to the local density approximation, the induced fields of the Cu atoms agree very well with experiments. We also present similar calculations for magnetic monolayers andthe corre-sponding induced host polarization in Cu andPd.     

Comparison of T1-weighted spin-echo and 3D T1-weighted multi-shot Echo Planar pulse sequences in imaging the brain at it.

The purpose of this study was to evaluate the ability of three dimensional T1-weighted multi-shot Echo Planar Imaging (3D T1w EPI) MR pulse sequence to provide comparable to T1w Spin Echo (SE) results in various diseases of the brain, during shorter acquisition times. Thirty-six patients (aged 30-74 years) with various indications were included in the study. All examinations were performed with a 1T MR scanner with a maximum gradient strength of 15 mT/m. The SE sequence lasted 3 min 50s and the 3D T1w EPI 59s. The quantitative analysis included number of enhancing lesions, signal-to-noise ratio of the enhancing lesions and contrast-to-noise ratio (CNR) between enhancing lesions and white matter in both sequences before and after i.v. administration of 0.1 mmol/kg gadopentetate dimeglumine. In addition, the percentage increase of enhancement was measured in each lesion of each sequence. The qualitative analysis included a) conspicuity of the lesions and b) presence of artifacts. The T1w SE sequence was significantly better compared to 3D T1w EPI in all quantitative measurements with the exception of CNR of enhancing lesions before contrast administration and the percentage enhancement. The conspicuity of the lesions did not differ between the two sequences. The EPI sequence presented with significantly more artifacts. We conclude that the 3D T1w EPI sequence could not be used instead of the conventional T1w SE, in routine imaging of the brain. Its overall diagnostic capability, could be useful only in uncooperative patients.     

Elimination of motion,pulsatile flow and cross-talk artifacts using blade sequences in lumbar spine MR imaging

The purpose of this study is to evaluate the ability of T2 turbo spin echo (TSE) axial and sagittal BLADE sequences in reducing or even eliminating motion, pulsatile flow and cross-talk artifacts in lumbar spine MRI examinations. Forty four patients, who had routinely undergone a lumbar spine examination, participated in the study. The following pairs of sequences with and without BLADE were compared: a) T2 TSE Sagittal (SAG) in thirty two cases, and b) T2 TSE Axial (AX) also in thirty two cases. Both quantitative and qualitative analyses were performed based on measurements in different normal anatomical structures and examination of seven characteristics, respectively. The qualitative analysis was performed by experienced radiologists. Also, the presence of image motion, pulsatile flow and cross-talk artifacts was evaluated. Based on the results of the qualitative analysis for the different sequences and anatomical structures, the BLADE sequences were found to be significantly superior to the conventional ones in all the cases. The BLADE sequences eliminated the motion artifacts in all the cases. In our results, it was found that in the examined sequences (sagittal and axial) the differences between the BLADE and conventional sequences regarding the elimination of motion, pulsatile flow and cross-talk artifacts were statistically significant. In all the comparisons, the T2 TSE BLADE sequences were significantly superior to the corresponding conventional sequences regarding the classification of their image quality. In conclusion, this technique appears to be capable of potentially eliminating motion, pulsatile flow and cross-talk artifacts in lumbar spine MR images and producing high quality images in collaborative and non-collaborative patients.     

Comparison of PD BLADE with fat saturation (FS), PD FS and T2 3D DESS with water excitation (WE) in detecting articular knee cartilage defects

The purpose of this study, is to compare the sequences: 1) proton density (PD) BLADE (BLADE is a PROPELLER-equivalent implementation of the Siemens Medical System) with fat saturation (FS) coronal (COR), 2) PD FS COR, 3) multi-planar reconstruction (MPR) with 3 mm slice thickness and 4) multi-planar reconstruction (MPR) with 1.5 mm slice thickness, both from the T2 3D-double-echo steady state (DESS) with water excitation (WE) sagittal (SAG), regarding their abilities to identify changes in the femorotibial condyle cartilage in knee MRI examinations. Thirty three consecutive patients with osteoarthritis (18 females, 15 males; mean age 56 years, range 37–71 years), who had been routinely scanned for knee examination using the previously mentioned image acquisition techniques, participated in the study. A quantitative analysis was performed based on the relative contrast (ReCON) measurements, which were taken both on normal tissues as well as on pathologies. Additionally, a qualitative analysis was performed by two radiologists. Motion and pulsatile flow artifacts were evaluated. The PD BLADE FS COR sequence produced images of higher contrast between Menisci and Cartilage, Fluid and Cartilage, Pathologies and Cartilage as well as of the Conspicuousness Superficial Cartilage and it was found to be superior to the other sequences (p < 0.001). The sequences T2 3D DESS 1.5 mm and T2 3D DESS 3 mm were significantly superior to the PD BLADE FS COR and the PD FS COR sequences in the visualization of Bone and Cartilage and the Conspicuousness Deep Surface Cartilage. This pattern of results is also confirmed by the quantitative analysis. PD FS BLADE sequences are ideal for the depiction of the cartilage pathologies compared to the conventional PD FS and T2 3D DESS sequences.     

Teaching decimal – binary conversion through an interactive exhibit

This note is a presentation of a didactic proposition about how to comprehend the conversion from the decimal into the binary system and vice versa with the aid of an interactive exhibit.     

Mushroom Polysaccharides and Lipids Synthesized in Liquid Agitated and Static Cultures. Part I: Screening Various Mushroom Species

The effect of four synthetic media containing glucose (initial concentration 30?g?l^?1) on mycelial growth, exopolysaccharides (EPS) and cellular lipids production was examined in 11 mushroom species after 12 and 16?days of culture in static- and shake-flasks. Fatty acid analysis of cellular lipids produced was also performed. Agitation had a positive effect on biomass production, glucose consumption and lipid biosynthesis. Media that favoured the production of biomass were not suitable for EPS biosynthesis and vice versa. Biomass values varied from ??1.0?g?l^?1 (Lentinula edodes) to ??19?g?l^?1 (Pleurotus ostreatus), while the highest EPS quantity achieved ranged between 1.6 and 1.8?g?l^?1 (for Ganoderma lucidum and L. edodes, respectively). Quantities of total cellular lipids varied between 2.5 and 18.5?% w/w, in dry mycelial mass for the fungi tested. Lipid in dry weight values were influenced by the medium composition. Cellular lipids presented noticeable quantities of poly-unsaturated fatty acids like linoleic acid. Compared to most of the mushrooms tested, lipids of Volvariella volvacea were more saturated. The ability of several mushroom species of our study to produce in notable quantities the above-mentioned added-value compounds renders these fungi worthy for further investigations.