NMR imaging of the diffusion of water at 37 degrees C into poly(2-hydroxyethyl methacrylate) containing aspirin or vitamin B-12

The ingress of water into poly(2-hydroxyethyl methacrylate), PHEMA, loaded with either one of two model drugs, vitamin B-12 or aspirin, was studied at 37 degreesC using three-dimensional NMR imaging. PHEMA was loaded with 5 and 10 wt % of the drugs. From the imaging profiles, it was observed that incorporation of vitamin B-12 into PHEMA resulted in enhanced crack formation on sorption of water and the crack healing behind the diffusion front was slower than for PHEMA without added drug. This was accounted for by the anti-plasticization of PHEMA by vitamin B-12. Crack formation was inhibited in the P-HEMA-aspirin systems because of the plasticizing effect of the aspirin on the PHEMA matrix. All of the polymers were found to absorb water according to an underlying Fickian diffusion mechanism. For PHEMA loaded with 5 wt % of aspirin or vitamin B-12, the best values of the water diffusion coefficients were both found to be 1.3 +/- 0.1 x 10(-11) m(2) s(-1) at 37 degreesC, while the values for the polymer loaded with 10 wt % of the drugs were slightly higher, 1.5 +/- 0.1 x 10(-11) m(2) s(-1).

The impact of peginterferon alfa-2a plus ribavirin combination therapy on health-related quality of life in chronic hepatitis C

Background/Aims: Peginterferon alfa-2a plus ribavirin improves sustained virological responses compared with interferon alfa-2b and ribavirin, or peginterferon alfa-2a alone in chronic hepatitis C. We examined the impact of these treatments on health related quality of life (HRQOL). Methods: Patients (n = 1121) were randomized to peginterferon alfa-2a weekly plus ribavirin or placebo, or interferon alfa-2b thrice weekly plus ribavirin. HRQOL was assessed with the SF-36 Health Survey and Fatigue Severity Scale (FSS). Results: Patients receiving peginterferon alfa-2a plus ribavirin reported better HRQOL than those receiving interferon alfa-2b plus ribavirin. These differences were statistically significant for three SF-36 domains and both FSS scores (p < = 0.05). Patients receiving peginterferon alfa-2a plus placebo had the least impairment; adding ribavirin significantly decreased five domains of the SF-36 and both FSS scores. Sustained virological response was associated with improvement at follow-up on all SF-36 and FSS scores. Conclusions: The effects of combination therapy on HRQOL and fatigue are less with peginterferon alfa-2a plus ribavirin than interferon alfa-2b plus ribavirin. Each medication in combination therapy with interferon and ribavirin, affects patients' quality of life differently. Understanding the relationship of specific therapeutic options to HRQOL may help physicians minimize the impact of therapy on HRQOL. (C) 2004 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

The Fa,b,c conjecture, I

In 1977 a five-part conjecture was made about a family of groups related to trivalent graphs and one part of the conjecture was proved. The conjecture completely determines all finite members of the family. Here we prove another part of the conjecture and foreshadow a paper which completes the proof of the other three parts.

The Fa,b,c conjecture is true, II

In 1977 a five-part conjecture was made about a family of groups related to trivalent graphs and subsequently two parts of the conjecture were proved. The conjecture completely determines all finite members of the family. Here we complete the proof of the conjecture by giving proofs for the remaining three parts. (c) 2006 Elsevier Inc. All rights reserved.