Sulfur is an underused by-product of the petrochemicals industry.R ecent research into inverse vulcanization has shown how this excesss ulfur can be transformed into functional polymers, by stabilization with organic crosslinkers. For these interesting new materials to realize their potential for applications,m ore understanding and control of their physical properties is needed. Here we report four new terpolymers prepared from sulfur and two distinct alkene monomers that can be predictively tuned in glass transition, molecular weight, solubility,m echanical properties, and color.

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Aims To review postpartum glucose tolerance in women with gestational diabetes and evaluate the role of formal 75 g oral glucose tolerance testing vs. fasting plasma glucose in screening for persistent abnormalities.Methods Retrospective study of 985 pregnancies over a 10 year period in a mixed ethnic cohort of women who underwent follow-up glucose tolerance testing at 6 weeks postpartum. Diagnosis obtained by oral glucose tolerance test was tested against that from the fasting plasma glucose value.Results There were 272 abnormal postpartum oral glucose tolerance test results (27.6%), with 109 women identified as having frank diabetes. Eleven of these (10%) had fasting plasma glucose £6.0 mmol ⁄ l, as did 62 of 114 cases of impaired glucose tolerance. A fasting plasma glucose concentration of ‡6.1 mmol ⁄ l correctly identified abnormal glucose tolerance in 199 of 272 cases (sensitivity 0.73). South Asian women were much more likely to have persistent abnormalities of glucose tolerance than were Europeans (32 vs. 15%, v 2 P < 0.0001).Conclusions A postpartum fasting plasma glucose measurement alone is not sensitive enough in our population to classify glucose tolerance status accurately. A formal postpartum oral glucose tolerance test is therefore needed to facilitate early detection and treatment.Diabet. Med. 27, 650-654 (2010)

The unique combination of the gas like viscosity and liquid like density of supercritical CO 2 (scCO 2 ) is exploited to blend poly(D,L-lactic acid) (P DL LA) and poly(ethylene glycol) (PEG) at near ambient temperatures. This novel process lowers the polymer blend viscosity and also permits incorporation of thermally and solvent labile protein based drugs. A series of blends are prepared with agitation in scCO 2 . Differential scanning calorimetry (DSC) data shows that miscible blends can be produced at moderate temperatures. A surprising region of miscibility is revealed between 8 and 25%w/w PEG. The properties of this miscible region are probed with high pressure parallel plate rheological studies, showing that the viscosity in scCO 2 is directly related to the miscibility. Using the particles from gas saturated solutions (PGSS) method, microparticles of these P DL LA/PEG blends are produced using scCO 2 and it is determined that the yields obtained are proportional to the miscibility of the polymers. Thus scCO 2 provides a unique route to low temperature, solvent free processing that accesses a window of miscibility that has not previously been observed. Finally, DSC analyses of these sprayed microparticles confi rm the presence of the same high miscibility region observed in the bulk samples prepared under supercritical conditions.

The effect of supercritical CO 2 on the viscosity and activation energy to viscous flow of P DL LA is investigated, using a high pressure parallel plate rheometer, over a range of temperatures (50-140 C) and pressures (5-12 MPa). The Cross model is fitted to the data to enable calculation of the zero shear viscosity and critical shear rate. A significant decrease in the viscosity is observed on increasing both variables; however, at high temperatures, the pressure effect becomes negligible. An increase in the critical shear rate is also observed on raising the pressure, indicative of a reduction in the relaxation time of the polymer. Manipulation of the Arrhenius equation shows a reduction in the activation energy to viscous flow as the pressure is increased. Together, these results show that the melt processing temperature of P DL LA can be reduced in the presence of supercritical and high pressure CO 2 .