A basic guide to hydrogels

Hydrogels are defined as three-dimensionally cross-linked networks of hydrophilic polymers capable of imbibing large amounts of water or biological fluids.They can be prepared from any water-soluble polymer or monomer, encompassing a wide range of chemical compositions and bulk physical properties. In the swollen state hydrogels are soft, wet and elastic materials that resemble natural living tissue, which makes them candidates for developing various biomaterials and dosage forms. This article provides a brief introduction to hydrogels, methods of their synthesis and properties

A practical approach to a multi-level analysis with a sparse binary outcome within a large surgical trial

Objectives: To assess the potential source of variation that surgeon may add to patient outcome in a clinical trial of surgical procedures. Methods: Two large (n = 1380) parallel multicentre randomized surgical trials were undertaken to compare laparoscopically assisted hysterectomy with conventional methods of abdominal and vaginal hysterectomy; involving 43 surgeons. The primary end point of the trial was the occurrence of at least one major complication. Patients were nested within surgeons giving the data set a hierarchical structure. A total of 10% of patients had at least one major complication, that is, a sparse binary outcome variable. A linear mixed logistic regression model (with logit link function) was used to model the probability of a major complication, with surgeon fitted as a random effect. Models were fitted using the method of maximum likelihood in SAS((R)). Results: There were many convergence problems. These were resolved using a variety of approaches including; treating all effects as fixed for the initial model building; modelling the variance of a parameter on a logarithmic scale and centring of continuous covariates. The initial model building process indicated no significant 'type of operation' across surgeon interaction effect in either trial, the 'type of operation' term was highly significant in the abdominal trial, and the 'surgeon' term was not significant in either trial. Conclusions: The analysis did not find a surgeon effect but it is difficult to conclude that there was not a difference between surgeons. The statistical test may have lacked sufficient power, the variance estimates were small with large standard errors, indicating that the precision of the variance estimates may be questionable.

Bringing poetry alive: a guide to classroom practice

This edited collection provides ideas and support for ways of 'bringing poetry alive' in the classroom at Key Stages 1,2 and 3, drawing on what is known to work and also exploring fresh thinking. It is designed to help both new and experienced teachers approach poetry teaching with greater imagination and confidence. The book is edited and introduced by Michael Lockwood and features chapters by experts who have taught poetry in different settings for many years, including contributions from poets Michael Rosen and James Carter. Professor Morag Styles of Cambridge University has provided a Preface. All the contributors have a connection with the University of Reading as lecturers, external examiners, current or former graduate students. The book includes the following sections: Introduction: Developments in Poetry Teaching 1: Reflections on Being Children’s Laureate – Michael Rosen 2: Teaching Poetry in the Early Years - Margaret Perkins 3: Actual Poems, Possible Responses - Prue Goodwin 4: Making Poetry - Catriona Nicholson 5: The role of the poet in primary schools -James Carter 6: Cross-Curricular Poetry Writing - Eileen Hyder 7: Teaching Poetry to Teenagers - Lionel Warner 8: Watching the Words: Drama and Poems - Andy Kempe 9: Literary Reading - Andy Goodwyn The book is intended for teacher educators,teachers and trainee teachers working with children aged 5 to 14 years.