Effects of degree of recycling on the rheology and processability of thermoplastic polymers

The effects of recycling on the processability of two injection molding grade thermoplastic polymers has been investigated. Recycling of a Polypropylene (PP) and a Polyamide (Nylon 6, PA6) has been simulated by repeated injection molding cycles, followed by blending of the processed materials with the virgin polymer. The flow properties of both the recycled materials and the blends have been evaluated by different rheological techniques, namely, capillary viscosity and MFI measurements, linear viscoelastic tests and solution viscosity number determination. The experimental results clearly indicate a qualitatively different behaviour of the two polymers upon recycling. PP shows a reduction of both viscosity and viscoelastic properties upon increasing the number of processing cycles, thus confirming the thermo-mechanical degradation of this polymer. PA6, conversely, shows an increase of both the melt and the number viscosity as the number of injection molding passages is increased. The results on PA6 suggest also that the thermally-induced re-gradation is accompanied by an increase of the degree of branching, that may be responsible for some peculiar features of the Virgin/Recycled blend rheology

CA 19-9 assay in patients with extrahepatic cholestatic jaundice

Serum concentrations of the CA 19-9 tumour marker were determined in 35 patients with histologically proven bilio-pancreatic malignancies associated with obstructive jaundice and in 35 patients with benign extrahepatic jaundice due to choledocholithiasis. At a cut-off level of 37 U/ml the sensitivity of this assay was 82.8%, but the specificity was very low (45.7%). Thus CA 19-9 can not be employed to differentiate between malignant and benign extrahepatic jaundice. Serial samples of CA 19-9 were achieved in 7 patients with benign and in 6 patients with malignant biliary obstruction, before and after the disappearance of jaundice. Serum concentrations of this tumour-antigen returned to normal concurrently with the bilirubin values only in patients with benign obstruction, remaining unchanged in all cases of malignancies. The data suggest that patients with extrahepatic jaundice should be evaluated by other examinations or by collecting serial samples for this assay

LH-RH analogue treatment in adenocarcinoma of the pancreas: a phase II study. Gruppo Ligure per lo Studio del Pancreas.

In this phase II study, we treated 7 patients, all males, with stage III or IV pancreatic cancer with goserelin (an LH-RH analogue). Goserelin was administered at a dose of 3.6 mg every 4 weeks. The tumour response was assessed by measuring lesions with US- or CT-scan studies, according to WHO criteria. No response was observed. The median survival was 8 months in locally unresectable tumours and 4 months in advanced disease. The accrual was actually stopped at 7 cases because there were no responses in either of our series or in those published during our study. The authors conclude that the treatment with LH-RH analogue alone cannot be recommended for further studies