Plasma-enhanced fluorination of YBa2Cu3O7−δ ceramics

The radiofrequency plasma technique involving mixtures of CF₄+O₂ gases has been applied to the surface treatment of high T_c superconducting oxides (YBa₂Cu₃O_7–). Investigation of the various experimental parameters of the process has shown that the improvement of the critical current density, J _c, mainly depends on the inlet precursor composition CF₄+%O₂, on the total pressure and on the reaction time. The presence of fluorine in the bulk of the ceramics has been observed from electron microprobe analysis, together with an increase of the Cu³⁺ content. The plasma-enhanced fluorination (PEF) treatment improves the superconducting properties of the materials: both values of the resistivity in the normal state and of the superconducting transition width are reduced and the critical transition temperature is improved by about 1 K.     

Phosphofructokinase from mantle tissue of Mytilus galloprovincialis. Purification and effects of phosphorylation on the enzymatic activity

Phosphofructokinase purified from mantle tissue of the sea mussel Mytilus galloprovincialis, was phosphorylated "in vitro" by the catalytic subunit of cyclic AMP-dependent protein kinase. The incorporation of phosphate gave rise to an activation of the enzyme by increasing its affinity for fructose-6-phosphate, by decreasing its sensitivity to the inhibition by ATP and by enhancing the effect of allosteric activators (5'-AMP and fructose-2,6-bisphosphate). In addition, the effects of phosphorylation on the catalytic activity are pH-dependent.     

Valence band density of states of small cobalt particles on Si(111) substrate

Small Co particles were prepared by sputter etching of a 4–5 nm thick island-like Co film deposited on Si(111) substrate. The density of states (DOS) of the valence band was measured by means of ultraviolet photoemission (UPS) during the sputter etching to monitor the formation of small Co particles. It was found that at a given thickness of the Co island the Fermi level was shifted by 1.8-1.9 eV toward higher binding energy and theDOS decreased or no states were detectable at the Fermi level. This effect was explained by the formation of small Co particles with electronic structure which is significantly different from that of the bulk Co.     

Models of Ballistic Propagation of Heat at Low Temperatures

Heat conduction at low temperatures shows several effects that cannot be described by the Fourier law. In this paper, the performance of various theories is compared in case of wave-like and ballistic propagation of heat pulses in NaF.     

Production of perovskite-like La1−xCaxMnO3+δ ferromagnetic thin films by electrochemical reduction

Ferromagnetic and perovskite-like thin films (<1m) of La1–xCaxMnO3+ have been routinely prepared by heat treatment of an amorphous La–Ca–Mn precursor. The precursor was electrodeposited cathodically in the absence of oxygen and water onto polished silver substrates from a nonaqueous solution of the components' nitrates. Analysis by X-ray diffraction and SQUID magnetometry shows these materials exhibit the appropriate structural and magnetic phases indicative of colossal magnetoresistance.     

Ronchi test with a square grid

We use a square grid in the Ronchi test. This grid allows processing of both the X and the Y directions when calculating optical path difference. We use trapezoidal integration to analyze the new patterns, since it does not have the smoothing drawback at the edges of the wave front.     

Functional and metabolic evaluation of the hypertrophied heart using MRI and31P-MRS

4. Conclusions Diastolic LV function and myocardial HEP metabolism are impaired only when LVH is caused by permanent pressure or volume overload, and not by a temporary increase in cardiac workload during part of the day as in elite athletes. Therefore, training-induced and pressure/volume-overload-induced LVH seem to represent different phenotypes of LVH, possibly related to genetic reprogramming which only occurs during permanent cardiac overload [17]. Moreover, there is an association between impaired LV diastolic function and altered myocardial HEP metabolism in patients with hypertension and in patients with aortic valve disease. Finally we did not find a correlation between myocardial HEP metabolism and LV mass in any of the groups studied. The latter indicates that LVH should be regarded as an epiphenomenon to cardiac overload, and not as a primary factor causing abnormal HEP metabolism.