Heat of formation of yttrium-bismuth alloys

In the Y—Bi system the formation heats were measured using a direct isoperibol calorimeter. The following values were found for the two known compounds:

     

Isoelectric focusing in low-denaturing media: visualization in renal disease of variation of the isoelectric point of albumin not related to a remarkable conformational variation

The isoelectric properties of serum and urinary albumin from normal subjects and patients with nephrotic syndrome have been investigated in various conditions of denaturation, obtained by using urea (0-8 M) as a support in isoelectric focusing. In normal human serum, albumin is rather acidic (pI = 4.7) when focused in glycerol while the denatured form obtained by exposing the protein to 8 M urea has a much higher pI (6.1). Albumin from nephrotic patients is acidic in glycerol but at very low levels of urea (2M) it shifts from pI 4.7 to pI 6.1; the same effect has been induced by treating albumin with activated charcoal at low pH. In order to obtain more information on urea-induced changes, we have recorded the circular dichroic spectra of albumin when exposed to the concentration of urea used in gels, and we found that no conformational transition occurs for urea concentrations less than 5 M. Taken together, these observations reveal that variation of the pI of albumin in nephrotic syndrome occurs mainly due to a dissociating effect of urea on charged substances bound to this protein.     

Deuterium isotope effect in (+)-glutamic acid hydrochloride

A study of the effects of deuterium substitution in (+)-glutamic acid hydrochloride is described. Solid state vibrational spectra depicting band shifts resulting from deuterium indicate that interatomic bond distances remain virtually unchanged. The cell volume expands only 0.05% upon deuteration, while the macroscopic linear and nonlinear polarizabilities are unaffected. The optical nonlinearity is therefore ascribed to the electronic nature of the hydrogen bonds.     

Fields,particles and universality in two dimensions

We discuss the use of field theory for the exact determination of universal properties in two-dimensional statistical mechanics. After a compact derivation of critical exponents of main universality classes, we turn to the off-critical case, considering systems both on the whole plane and in presence of boundaries. The topics we discuss include magnetism, percolation, phase separation, interfaces, wetting.     

Heat of formation of PraseodymiumBismuth alloys

In the PrBi system the heats of formation were measured using a direct isoperibol calorimeter. The composition and equilibrium state of the samples have been checked by chemical, metallographic and X-ray analyses. The following values were found for the two known compounds (reaction in the solid state, 300 K):

The results obtained, compared with those already achieved in other REBi systems, are briefly discussed.